fixes #36. plug updates

Latest version of plug breaks routing/dispatching.
The plug adapters are expecting just a conn returned,
no {:ok, conn}. Plus, the router (which is acting as
a plug) needs to have init/1 defined for initialization
of the options.
updating mix.exs to reflect elixir req.
fixes issues with router crashes

corrects tests as well. not sure why i didn't do this in the first place
Refactor dispatcher to handle new Plug format