skinny 1.3.4 (new formula)

This is new formula proposal. Skinny Framework is a famous web framework in Scala.
http://skinny-framework.org/
We already supports homebrew installation from our alternative repository for months past.
https://github.com/skinny-framework/homebrew-alt

Thank you in advance.
@mikemcquaid Done. Thanks to your advice, this formula has been much improved!