2.5 Branch

2.5 Branch
==========

* Changed wmOperatorType, removing init/exit callbacks and adding cancel
  callback, removed default storage in favor of properties. Defined return
  values for exec/invoke/modal/cancel.
* Don't allocate operator on the stack, and removed operator copy for
  handlers. Now it frees based on return values from callbacks, and just
  keeps a wmOperator on the heap. Also it now registers after the operator
  is fully finished, to get the correct final properties.
* Changed OP_get_* functions to return 1 if the property is found and 0
  otherwise, gives more readable code in my opinion. Added OP_verify_*
  functions to quickly check if the property is available and set if it's
  not, that's common for exec/invoke.
* Removed WM_operatortypelist_append in favor of WM_operatortype_append
  which takes a function pointer instead of a list, avoids macro's and
  duplicating code.
* Fix a crash where the handler would still be used while it was freed by
  the operator.

* Spacetypes now have operatortypes() and keymap() callbacks to abstract
  them a bit more.
* Renamed C->curarea to C->area for consistency. Removed View3D/View2D/
  SpaceIpo from bContext, seems bad to keep these.
* Set context variables like window/screen/area/region to NULL again when
  leaving that context, instead of leaving the pointers there.

* Added if(G.f & G_DEBUG) for many of the prints, makes output a bit
  cleaner and easier to debug.
* Fixed priority of the editors/interface module in scons, would otherwise
  give link errors.

* Added start of generic view2d api.
* Added space_time with some basic drawing and a single operator to change
  the frame.