some topic-list simplification
catching up with the master

Merge remote-tracking branch 'upstream/master'
further simplification over all, changes include: flatter button style, styling admin table, topic-list style
merging with the new category nav feature

Merge remote-tracking branch 'upstream/master'
category nav style
Merge pull request #1582 from awesomerobot/master

continuing default theme simplification/fixes