(closes#5568)
Several strategies in here:
- Move uiCombobox() from inside the render function to class variable
- Don't render stuff like the raw tag editor when it's collapsed
- Don't show as many fields/combos on hover
- Don't instantiate fields (like universal/more) until they're actually shown
- Bind the combo on enter selection not on update selection
uiCommit is getting kind of big as we add more to the commit pane.
I'm going to split it up and put the field rendering code into a separate
module, similar to how uiEntityEditor embeds uiPresetEditor for the fields.
This allows us to add a few more fields that users can set on their changesets
(like hashtags, source), and even hide them under a "Add field" dropdown.
