Play 2.2.0-RC2
Drop webjars down to 2.2.0-RC1 which works with play 2.2.0-RC2.
Bump dependencies for offline mode.

* Bump to play 2.2.0-RC2
* Add slick dependencies now that it's a featured template
* Add in sbt 0.13 plugins.
Don't specify sbt version, since we now support more than one.
Bump to latest sbt-rc with Atmos + Play 2.2.0-RC2 support.
Merge pull request #62 from typesafehub/wip/havocp-play-22-rc2

Fix offline usage of activator with current templates