2.5: Added basic insert/remove keyframes from UI buttons.

- I key over a button inserts a keyframe.
- Alt+I removes a keyframe.
- With right mouse button a menu with these options pops up.
- Buttons are colored green if the property is animated, yellow
  if it is on a keyframe. I followed the colors from the UI
  mockups, but the flicker on keyframes seems too distracting in
  practice?

- This only works for properties on the ID itself at the moment,
  path callbacks need to be filled in for all structs but mesh
  still.
- It doesn't work when you're over a related label, that needs to
  be made to work.
- I made it insert keyframes outside of any keyingset. Not sure
  how this is supposed to integrate?

source/blender/editors/include/UI_interface.h

@@ -131,6 +131,8 @@ typedef struct uiPopupBlockHandle uiPopupBlockHandle;
 #define UI_BUT_DISABLED		(1<<18)
 /* dont draw hilite on mouse over */
 #define UI_NO_HILITE		(1<<19)
+#define UI_BUT_ANIMATED		(1<<20)
+#define UI_BUT_ANIMATED_KEY	(1<<21)
 
 /* Button types, bits stored in 1 value... and a short even!
 - bits 0-4:  bitnr (0-31)
@@ -626,5 +628,9 @@ typedef void (*uiPanelCreateFunc)(const struct bContext *C, uiLayout *layout);
 void uiRegionPanelLayout(const struct bContext *C, struct ARegion *ar, int vertical, char *context);
 void uiRegionHeaderLayout(const struct bContext *C, struct ARegion *ar);
 
+/* Animation */
+
+void uiAnimContextProperty(const struct bContext *C, struct PointerRNA *ptr, struct PropertyRNA **prop, int *index);
+
 #endif /*  UI_INTERFACE_H */