Start timeline selection interface
Better timeline selection interface within tracks
Merge branch 'master' into timeline
Pause and reset play outside selection

This is maybe a little questionable if we start outside...
Enable record segment editing

Lots of mess, mainly around a Formatter[Segment]
allow overflow for slot record labels, need fixing with z-index or something else perhaps
set max height to asset displays in slot view
More fixes for record relocation
Determine click vs. select by time, not space
Remove div layer on timeline tracks
TableIdMap: maps of TableRowIds
Minor change to Volume.records, preparing for more
Generate volume summary client-side
Remove unused volume.categories
Upgrade DBIs: postgresql-async 1.2.15, 9.3-1102
Replace some implicit def = new with classes

Even if they don't have better performance, they do provide better
checking, which also caught a bug in SQLType.array
Improved and more concise error checking for moveRecord/sql
add link rel to canonical url for search engines
Simplify, optimize volume.sessions access

Does break the minimal amount of volume_inclusion that was working, but
oh, well.