Python API

Bugfixes 2.49b

Mathutils (quat_a*quat_b) was broken, returned (quat_a*quat_a) instead.
Support for editing properties IpoCurve.driverBone and IpoCurve.driverBone2 and modifies IpoCurve.driverChannel to allow OB_ROT_DIFF.
Documentation corrections.
Support for rendering background scenes different from the active scene.
scene.render.render() now behaves the same in interactive and background mode
scene.render.saveRenderedImage() now works correctly in background mode
Armature active bone can be set.

FBX Export, Incorrect formatting that broke some converters.
BVH Motion Capture Import, Did not support single rigid body objects. [bug #18949]
OBJ Import, fix for importing of transparent faces from .mtl files - ZTrans now is set for them as well. (improves import from SketchUp)
Collada export, Empty material slot would raise a python error.
Collada import, fixes for increased Sketchup interoperability and more.
Quake MAP Export, empty nodes were not exported, also noticed files were invalid if there were no meshes or surfaces.
Quake MAP Export, had support for single triangular brush unnecessarily disabled.
Quake MD2 Export, Fix for vertex normals [patch #19206]

New external bundles from meta-androcto, for the first time released officially!
See Extensions:Py/Scripts/Catalog/Bundles

Wavefront OBJ support to import & export curves as OBJ native curves (rather then a bunch of edges)
Wavefront OBJ X90 option for export to write files without rotation.