This reverts commit d364a7b4.

Before, 3 Rigify panels:
{F12837079}

After, single Rigify panel with sub-panels:
{F12823002}

Originally mentioned in T88711, where it didn't spark much discussion, hopefully meaning it's non-controversial.

This patch proposes moving the many panels of Rigify into sub-panels under a single Rigify main panel, in order to reduce clutter in the Properties Editor's Armature tab. This also makes it easier to add more Rigify features in the future, since new panels won't make the overcrowding of this tab even worse.

It also unifies some of the available functionalities between edit and pose mode, where limiting a workflow to only pose mode didn't seem necessary.

Reviewed By: angavrilov

Differential Revision: https://developer.blender.org/D13914

Fix the invalid argument passed in place of operator id.

Reviewed By: Nutti

Differential Revision: https://developer.blender.org/D13980

Patch D10034

Prior to this patch, attempting to modify an existing bolt would
*replace* the object's mesh data block with a new one and remove the
original. This removal would essentially delete all linked duplicates.

Now the original mesh data block is modified in place, which avoids
having to copy anything between new and old object data blocks
(materials, names, etc), and causes all linked duplicates to reflect
the changes as users would expect.

    Patch by Robert Meerman (meermanr)
    Thanks Robert

    This changes the order in which presets are shown by the "Add Bolt" operator such that they follow natural numeric ordering.

    Before:

        Default
        M10
        M12
        M2
        M3
        M4
        M5
        M6
        M8

    After:

        Default
        M2
        M3
        M4
        M5
        M6
        M8
        M10
        M12

Also put an " - Old" by the name of the exporter.
The intention is that we won't load the Python exporter, but if a user wants
it, they can enable that addon.

Also put an " - Old" by the name of the exporter.
The intention is that we won't load the Python exporter, but if a user wants
it, they can enable that addon.

Update from @TheRedWaxPolice, with some adjustments
in the spreadsheet editor, node editor, and list items.

* fix default open() encoding from strict system character set to utf-8
ignoring all other characters so Blender should no longer reject exotic
input pov files as mostly user declared names will probably get changed
in that process and likely everywhere the same way.

Instead of re-implementing BLI_string_flip_side_name, use the python function that was exposed in D12322.

Reviewed By: sybren

Differential Revision: https://developer.blender.org/D13191

fix useless enumeration providing index in place of string

Using the shortcut to reset rotation in camera view (default: quick 'cltr + alt + MMB'), the viewport stay centered, even with a pan.

Previously, the view would jump by following cam rotation.

POV: Add primitives workspace tools icons, blurry reflections, equation based isourface ; various fixes

* fix tiny formatting of quotes, docstrings, parenthesis
* fix pov centered worspaces
* fix (revert) bad default for text block insertion
* fix primitive exports sorted by most frequent for (slight) speed up
* fix some uninitialized hairstrand root diameter variable
* fix extracted function for CSG inside vector
* fix too big size of proxy mesh for ininite plane caused it to blink
* fix end of render speach error handling
* fix max specular value to better map out under a texture influence
* fix emit, ambient, translucency shading properties UI broken post 2.8
* add workspace tools icons for pov primitives
* add a user input equation based isosurface primitive
* add micro normals based blurry reflections (glossy UI slider)

Fix io_mesh_atomic, utility panel: changing the atom material did not change the material of 'normal' and 'skin' sticks

Reason: a material change of also 'normal' and 'skin' sticks was
simply not included. Recently, it was done for 'dupliverts' sticks
(see https://developer.blender.org/rBA84f5f4699232decc2f1a8694312680b9e5159462)

Now, the atoms and corresponding sticks of any representation ('dupliverts',
'skin' and 'normal) change the material when using the utility 'Change atom shape'
in the 'Utility Panel'.

Reason: the planes used for the instancing vertice structure were
visible at once because their size was as large as the stick diameter.

I decreased the size of those planes by a factor of 100, everything is
fine now

This patch is a continuation of D8519, was also suggested in T88711#1170152.
It adds a checkbox for each feature set in the Rigify Preferences, to disable/enable that feature set without having to completely remove it from the file system.

Challenges that were hopefully successfully tackled:
- Keep list in sync when user manually adds or removes things through the file system instead of the "add/remove feature set" buttons in the UI.
- Avoid re-building the feature set list all the time so that the checkbox states can actually be stored when the user exits Blender.
- Disabling a feature set means calling its unregister function, then rebuilding the rig types and metarigs lists/menus.
- Some renaming slipped in because I found the variable name "feature_set" a bit confusing. If needed, I could split this change into a separate patch or just forget about it, but I think the longer names help here.

Testing would be welcome, since things turned out a bit more tricky than expected.

In a follow-up patch I would like to do a code quality pass, to split the code a bit better here. There is a bit too much stuff in __init__.py in particular. I will get started on that when this gets close to being finalized.

Reviewed By: angavrilov

Differential Revision: https://developer.blender.org/D12260

Fix io_mesh_atomic, utility panel: changing the atom material did not change the material of the sticks

Reason: a material change of both was simply not included.

Now, the atoms and corresponding sticks change the material when
using the utility 'Change atom shape' in the 'Utility Panel'.

Reason: hidden objects cannot be modified by 'bpy.ops.object.shade_smooth()'

The surface of sticks, which are in an instancing vertice structure,
are now correctly smoothened when option 'Smooth' of the PDB importer is
selected.

Property 'material.diffuse_color' is now set such that one can see the
color of the atoms in also the 'Solid mode' of the Viewport.

Please enter the commit message for your changes. Lines starting

Removal of code, which belongs to the good old times of Blender <=2.79
and which does not make sense anymore in higher Blender versions.

- Error message "'NoneType' object has no attribute 'nodes'" because of
wrong handling of the material properties.
- After bug removal, the standard size and material properties can be
assigned to all selected atom strctures.

Changes
- All properties of the Principled BSDF shader can now be set in the
  data file for each element.
- Some important properties for Eevee are mentioned as well.

Remember: a custom data file contains the size and material properties
for each element. With this, the sizes and material properties of selected
atoms in an atomic structure can be changed at once. The user can therefore
store her/his own material properties inside this file and use it at any
time for any atomic structures.

of the special objects (F2+, F+ and F0 centers) in the section 'Change atom shape'
got updated for eevee and cycles.

for both, Eevee and Cycles, is sufficient, no need to have an additional
ball with emission for Cycles.

This shouldn't have had an effect, since the soft max was
larger than the max, but it is still incorrect. Caused by a
typo in rBA104ba1c5682016a55. Thanks to @MKRelax
for pointing this out.