Refactored Auto-Keyframing to make it easier to add more options. There are now three "states" for auto-keying: off, add/replace keys, replace keys.
Description of modes:
1) No auto-keying is done
2) Add new keyframes or replace existing ones if possible (old behaviour)
3) Only modify existing keys, but not insert new ones.
Internally, I've moved the auto-keying settings out of G.flag and U.uiflag and moved them into their own variables in Userdef, and provided some macros to access those easily. As a result, old auto-keying settings are currently lost.
Also, removed the manual calls to insertkey done in pose-relax. The reason auto-keying didn't work before was because the bones didn't have the BONE_TRANSFORM flag applied. Now, these are set temporarily.
Todo(s):
* Make icons for the TimeLine header menu (currently just a text menu)
* Add version-patches for old files
* Double-check code for all places that use auto-keying (i.e. PoseLib)
38a33eb7da