Use net-http-follow_tail gem.
Use JSON instead of YAML for IPC messages.

Because YAML has performance problems:

https://gist.github.com/broquaint/5520179
Always use integers for offsets.

For sanity + consistency.
Couple of small front_page_controller fixes.

The cache key name was slightly wonky and the without the combo check an
exception would be raised when it was empty.
Use SoupStash::Model::Game for model fields.

So the rails app no longer owns the game fields which is a step in the
direction of pulling all the non-web code out.