Blender Git Loki

Proportional editing support for the action editor.

There are a few things here which are not so nice:

* Position of proportional edit circle is not centered on data
(difficult to predict positions here since those are completely custom,
will probably be positioned at center of area later instead)

* Result is flushed to curve handles only at the end of the transform,
so if people have the graph editor open they will see handles lagging behind.