Blender 2.48a

* GE: Sensors could access removed objects via Scenegraph, causing crashes
* GLSL: ATI drivers crashed on "show pivot" for rigid body constraints
* GE: using Bullet could cause memory leaking
* UI: Panel cleanup in Constraints.
* Python: Epydoc cleanups
* Python: now better compatibility with Python 2.3
* Python: on script errors, Blender objects didn't get correct cleared memory, causing crashes
* Import: PLY files didn't read vertex colors
* Export: VRML script didn't export with images.
* Updated X3D and VRML importers
* Armature editmode: "Switch Direction" could cause infinite loop
* SSS render: with render option SSS disabled, textures didn't show up
* Added undo saving for Vertex Group operations
* New option for pressing NumPad-0 didn't work properly in all cases
* Animation: Pressing I-key (insert key) crashed when no Object was active