Blender Git Loki

Action Editor: Experimental tweak to ordering of buttons

This commit is an experiment exploring the relationship between the action
management buttons (i.e. action selector + pushdown/stash, and soon a few others)
and the filtering stuff (i.e. summary, only selected, etc.)

The old ordering meant that the filtering stuff was consistently in the same
place beside the mode selector, meaning that the order was "common stuff, then
editor specific stuff", this was not that great on smaller windows, where there
important stuff was often out of view.

This new order places greater emphasis on the parts which are likely to be more
important. It also allows us to have a better hierarchy/flow; this is especially
because we'll soon introduce a way to specify which datablock "level" the
action comes from, so going from "level -> action -> filters within action" will
make more sense.