Split project settings from style/source browsing/switching/etc.
Square off megamenu on source UI.
Merge branch 'master' into one-thing-at-a-time

Conflicts:
	templates/history._
	templates/modaluser._
	templates/source._
	templates/style._
Merge cruft.
Merge branch 'master' into one-thing-at-a-time
Merge pull request #344 from mapbox/one-thing-at-a-time

Split project settings from style/source browsing