Refactor User#update_last_seen! and User#update_tracked_topics
some topic-list simplification
catching up with the master

Merge remote-tracking branch 'upstream/master'
Better blockquote button in Markdown editor when non-traditional markdown linebreaks
are enabled.
Oops JSHint again :(
)
further simplification over all, changes include: flatter button style, styling admin table, topic-list style
fixes wrong placement of expect in header integration test
fixes wrong placement of expect in View Topic integration test
Changed breadcrumb dropdowns
Use the debounce parameter instead of hard-coding 100
FIX: weird scroll position on visiting a topic page for the first time (chrome OS X, maybe mobile safari too)
merging with the new category nav feature

Merge remote-tracking branch 'upstream/master'
category nav style
require `X-Frame-Options: SAMEORIGIN` for clickjack prevention
Merge pull request #1582 from awesomerobot/master

continuing default theme simplification/fixes
Declare rack-protection dependency explicitely
making post-info text brighter, making category nav dropdown text smaller and bold
Merge pull request #1586 from awesomerobot/master

making post-info text brighter, refining category nav dropdown
Version bump to v0.9.7.2
Merge pull request #1585 from raul/prevent-clickjacking

Require `X-Frame-Options: SAMEORIGIN` for clickjack prevention