Thanks to Sanc Tuary for the bug report! Bug #35040

The bbone elbow was causing weird twisting and sharp bend angles
even when smooth elbow/knee was fully disabled.  Now fixed.

This fix, however, exposes bug #34532 in Blender, so for the time
being the transition between smooth/sharp elbow is a jumpy one.
This is less objectionable, however, then the weird twisting
that was happening, as bug #34532 can be worked around by the
animator, whereas the weird twisting could not be worked around.

Arm/leg rig upgrades:
  - Arms and legs no longer scale with their parents, which was
    problematic when e.g. the torso of a character did
    squash-and-stretch causing the arms/legs to distort and shear.
  - Squash-and-stretch for both FK and IK rigs.
  - Rubber hose controls.

Misc changes/bugfixes:
  - Rigify now locks all pose transforms for non-control bones
    automatically.
  - The README file now correctly reflects the new rig-type API.
  - Scrubbed the code for unused variables and imports.
  - PEP8 cleanups.

rig types.

Contains buttons for operators that are useful when developing for
Rigify.  For now, it's buttons that generate python code for recreating
selected armatures.

I have updated the rig type API to be a bit clearer based on my
interactions with Kfir from PitchiPoy.

I've also disabled the "delta" rig type, as it is very obscure and
mostly just confuses people.

This required changes to both the default human metarig and some of
the rig types.  This updates the naming scheme to match new
best-practices, as per the CGCookie Flexrig.

This makes it much easier for e.g. someone to branch Rigify for
custom purposes, since there won't be weird name conflicts.

Also changed from using __import__() for dynamic imports to using
importlib.import_module().  This simplifies the code and should
be more robust.

Finally, misc pep8 cleanups.

It is now able to write out all relevant layer data.
Also, the script generated can now be directly run, for testing.

are now dynamically pulled from python files in the metarigs
directory.  This makes adding new metarigs pretty painless.

WGT objects were sticking around even when the user deleted them
since they were being used by the bones for visual appearance.  This
meant that if the user deleted the WGT objects in order for Rigify
to regenerate them the next time around, Rigify would fail.

Rigify now checks for this circumstance and handles it appropriately.

The biggest fixes relate to keeping ID data modification out of
draw methods.  This was breaking Rigify with the current API.

Secondary fix was to move widget meshes to match the bones, even
if the widget meshes already exist.  It's nice for when the user
is progressively tweaking the metarig.

When using default UI_UL_list, one should always spully a custom ID, else collision inside an area are quite likely...

Thanks to Jack Simpson for the heads up!

From the report:
  This patch fixes a bug that rig modules of 'arm' and
  'leg' cannot be loaded failing as follows:
  
  Rigify: No module named 'rigify.rigs.biped.arm.biped'
  Rigify: No module named 'rigify.rigs.biped.leg.biped'

I couldn't reproduce the error, but new code works on my system
just as well as the old code, so I assume this serves to make the
code more robust on a larger range of systems.

Thanks Shinsuke!

Blender increased object name length limit from 21 to 63 at some point,
and I hadn't update Rigify to reflect that.  This enables better reliability
with respect to widget shapes.

make addons blender versions consistent

the biped leg rig.

- dont import *
- dont use builtin names for vars
- strip trailing white space

- Check for keymap availability to suppress warning messages when running
  blender in background mode