update build ... completely.

Update to scala 2.10, update socko to match. This required some simple
changes having to do with duration imports and import the actor
dispatcher to bring in an execution context for futures. add a number
of plugins including ensime, scalastyle and release. remove the jrebel
revolver plugin as it seems you're no longer able to get a free scala
licence. update the overall build with some cleanup touches around
prompts etc.