Blender Git Loki

Patch #4980, by Joshua Leung (aligorith)

This enables finding data in the Outliner.
Usage: Fkey (partial strings), CTRL+Fkey (partial strings, case sensitive).
SHIFT+Fkey to repeat a search, this cycles around.

Extra changes:
- button popups to enter strings now starts activated.
- outliner either shows for Armature the Bones, or Posechannels or
Editbones, depending the mode. Was needed to make searches meaningful.

Although Joshua did very good work on the key functions, there were a couple
of issues in his code, and problems in Outliner code, that didn't make it
all work nicely. So, this is quite a revised patch. :)

Full review log can be found in the patch tracker.