Fix root route splat not matching and incorrect match order. Close #222
Fix unused var
Update Topic.delete/1 to only delete inactive topics
Allow controller action/2 to be overridden for custom action handling per #224.
Add documentation for overriding controller action/2
Add Socket get_assign/4 and assign/4 for specific channel/topic access
Refactor channel/topic assigns keys for faster lookup
Make Phoenix.Channel a behavior. Close #225