* Expose 3D view camera zoom and offset, needed if you want to precisely
reconstruct camera parameters.
* Rename SpaceFileBrowser.operator to active_operator, to avoid conflict
with c++ keyword.
ui/ --> startup/bl_ui
op/ --> startup/bl_operators
scripts/startup/ is now the only auto-loading script dir which gives some speedup for blender loading too.
~/.blender/2.56/scripts/startup works for auto-loading scripts too.