Changes to categories list to match Forum_v4.pdf

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Topics page

per Forum_v4.pdf.
https://www.apptrajectory.com/heather161d03/keyword/stories
Refactoring

Pull out a lot of deprecated style, reorganized the remaining style so
the new stuff is below the old stuff
https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Refactor forum header

Move it into the .forem class so it doesn't bleed into non-forem pages.
https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Style to topics#show

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Refactor menu

Floated it instead of using absolute positioning, so we can have more
than one instance on a page.
https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Generalize header style

We were treating some h2s with one style and some with another style; it
makes more semantic sense to treat the one style as actual h2s and the
other as h3s.
https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Keep user info at top of td

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Margin tweak to #description

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Refactor form style

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Tweaks to topics#new

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248
Style to .subject more consistent

https://www.apptrajectory.com/heather161d03/keyword/stories/15621248