Blender Git Loki

UI Lists: Add Ctrl+F for searching, brings search field into view

The Ctrl+F is a general UI list feature. You can hover any UI list and
press Ctrl+F now to open and activate the search field. If needed the
view is scrolled to make it completely visible (with some additional
margin). Plus, the view is updated to keep the search field visible
while typing.

The latter part is also a text button feature. When you activate a text
button (that doesn't have a search menu attached, which causes further
issues), the UI code makes sure it's visible and keeps it visible while
typing.

This could go into master (after some functionality review), I'll check
on that in a bit.