Add simple Tag.search function

Test assembla-87
Pass Map to input to avoid redundant mapping

Optimization only.
Give pageActions results a proper type

Remove redundant code in the process
Improve tag validation
Fix SlotAsset.segment, hopefully
Copy, don't move files on admin upload
Add support for pixel format conversion

A bit messy, possibly dangerous, but seems to work
Fix download mimetype for singleton slot assets
Add language metric and ingest
Fixup language schema
Implement ffmpeg lockmgr using pthreads

Java locks seem to be crashy
Only show thumbs if we have permission
tags mostly; ajax almost complete.
Add Tag.getVolume and getSlot(all = true) aggregation

Closes assembla-157
ajax tags complete.
Merge remote-tracking branch 'remotes/origin/master' into gui

Conflicts:
	app/models/tag.scala
	app/views/slot/view.scala.html
merge conflicts