the rig.

- Flipped the roll values on the default human metarig spine and neck.  This
  makes bending the rig forward have a positive rotation value, and bending
  back have a negative one.  More in line with user expectations.
- Improved get_pose_matrix_in_other_space() to account for bones with
  "inherit rotation" and/or "inherit scale" turned off.
- Added a text file giving credit to people who have contributed to Rigify
  financially or otherwise.

Moved operator registration for rig UI into the register function.  Not
really necessary, since the generated script doesn't act as an addon.  But
it keeps everything in one place.
Also added an unregister function for absolutely no reason.

Clean-up of the IK/FK snapping code.  Should be much more maintainable now.

Also changed rig id generation.  Rig id's now consist of a random
alphanumeric string 8 characters long, with the smallest 8 digits of seconds
since the epoc (in hex) at the time of rig generation appended on the end.
This results in a 16-character string that is ludicrously unlikely to
have any collisions between rigs.  36^8 * 16^8, with the 16^8 being very well
distributed over time.  Ah... paranoia.

- Added IK/FK snapping (both directions) for legs.
- Cleaned up another operator so that it works with undo.
- PEP8 cleanups. 

was missing undo push as Joshua pointed out.

Also cleaned up how some of the operators work.  They weren't playing nice
with undo.

So far just IK->FK for biped.arm.

extensions_framework: added ef_callback pseudo-property type for invoking custom draw methods in property_group_renderer

- Summary page now lists border render
- ore.prepare now changes border render off
- ore.prepare now changes full sample off, then save buffers (old was just save buffers which can't be changed if full sample is on)
- A small piece of text that warns about the upload making Blender seem frozen
- Bug fix: ore.prepare() couldn't be called in the old way. The new API prevents changing data during layout drawing. The original ore.prepare operator was changed a bit to not require the call
- Bug fix: Completed / pending / rendering sessions didn't work. Same issue as above: cannot change data during draw functions. Fix is simply removing the problematic call as the list is already generated elsewhere

pep8 edits for povray, also dont use string addition for textblock contents, write newlines separate.

* More Code cleanup, please watch and learn. :) 

also enable preset menu

* Code cleaunp

Notes:
*Why do we have some empty panels with no actual content?
*Why is split used when there is only 1 column?

The Povray script has always been some kind of example for other exporters, the UI code need some more cleanup for sure!

Fixed some other problems with solids script regarding weird names which messed up truncation of verts and edges

- Handle situation when last point of path segment has got the same position,
  as first segment point. It used by Illustrator to set up handles of first
  point and to make segment closed.
  Not sure about standatr about this, maybe SVG files from other editors should
  be handled in different way, if it'll be issues -- could be easily fixed.
- Use black fill as default (all viewers/editors use this).

from Michalis Kamburelis (kambi)

- Fixed rotation matrix
- Fixed unneeded deformation caused by interior transformation for
  used objects (different tags should be handled differently),
  also, SYMBOL tag could have viewBox
- Implemented parsing of colors in rgb(r,g,b) notation