Mhx importer: added icons for pin buttons. changed disable layers so the first layer on with the active posebone remains.

commented out line 784 #    bpy.types.DATA_PT_texface.append(_add_tface_buttons)

please test scripts in the ui before committing changes.

rectangular area lights had wrong coordinates (probably achievable with proper matrix but swapping and negating axis seems ok for now)

Plus a few styling enhancements.

[[Split portion of a mixed commit.]]

* Volume calculation and mainfold check code by Benjamin Lauritzen (Loonsbury)
* Updated API revision

Fixed a type error for dimensions of rectangular area lights 

Temporary mainfile used to be saved to current working directory
which isn't always available for writting.
Save temporary mainfile to temporary directory.

* Measurement of face normals by TNae + extended to cover all cases.
* Patch link: http://blenderartists.org/forum/showthread.php?177800-Measure-script-%28Blender-2.5x-only%29&p=1896219&viewfull=1#post1896219
* Grouped measured values inside boxes.

It was broken since 2.58a and problem was caused by sysconfig
module which tried to parse python configuration header (pyconfig.h).

Use dirname(platform.__file__) to determine libpath for python.

* fix for grab, click error
thanks to Gaia Clary for his hard work on this script.

adds a Mouse&text grouped modus (with a visual boundingBox), mouse and font be sized separately,
settings will be stored along with the blend file now.

MAde some changes for future improments. Basicly conserning transferring mmultires data between blender and 3d-coat.