* 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).
