Cross-publish for 2.10 and 2.11

Adds cross publishing for scala 2.10 and scala 2.11. Includes scala 2.10 to be backwards compatible and that dependent projects can just use `%%` for their argot dependency.

To be able to cross publish both scalatest and grizzled were updated (for scalatest usage of deprecated functions were replaced by new ones), also sbt and the ls-sbt plugin had to be updated.

This should replace pull request #10