Subreddit routes working

Now /r/:subreddit will display that sub
Added select box for sort options

Didn't hook it up yet.
Change how subreddits are handled

Added a 'cachedSubreddit' private var to the posts factory to properly detect when subreddit is changed if the passed sub===current.sub.
Kind of wonky still, just now facepalming because I'm clearing current, where current.sub is stored.  Probably need to fix.