* Added crash fixes for loading old files with Actions/Armatures in them. Was caused by usage of some old globals still and the functions in question not performing NULL checks on the validity of the data they're given.
* Added back reorganise action channels tools (shift/ctrl-shif pageup/down) for Action Editor. These are only available in 'Action Mode' only.
* Tidied up Action Editor/Dopesheet tools code - removed various unused things, and also, added an API call in anim_deps.c to send the correct notifiers, since I anticipate that they're likely to require a few context checks which would be better to centralise than copy+paste everywhere.
Note to Ton: could you have a look at this notifier stuff here? I'm not sure which ones I should be sending...
* Also added a few assorted comments in various places
Think global, act local!
The old favorite G.scene gone! Man... that took almost 2 days.
Also removed G.curscreen and G.edbo.
Not everything could get solved; here's some notes.
- modifiers now store current scene in ModifierData. This is not
meant for permanent, but it can probably stick there until we
cleaned the anim system and depsgraph to cope better with
timing issues.
- Game engine G.scene should become an argument for staring it.
Didn't solve this yet.
- Texture nodes should get scene cfra, but the current implementation
is too tightly wrapped to do it easily.
* Brought back clean (OKEY), sample (Shift-OKEY), and delete (XKEY/DELKEY) tools for the Action Editor.
Currently clean uses a predefined threshold (as a rna-prop, though it's still lacking the popup to set this when it is called)
* Added new file for 'destructive' keyframe operations/tools.
* Got keyframing.c compiling. Now, some of these tools need to be operatorised. Also, the API there might change when enough of the system is stable for RNA-IPO work to take place (so that it can be tested).
* Brought back backend for editing keyframes IPO/IPO-Curves. Did some refactoring work here that will still have to be verified when operators using them are added.
* Animation channel filtering code now returns the number of channels filtered (for Action Editor to set totrect of channels - TODO still!)
* View2D - made function to check if mouse is in View2D scrollers an API function
* Renamed keyframe related files. The old names were too clumsy.
* Started porting click-select operators for Action Editor. These don't work currently, as the events are being stolen by the markers. This needs to be fixed ASAP.
