Bump version to 1.1.0-SNAPSHOT

Also moves to Scala 2.11.4.

Mima is disabled since `1.1.0` won't be binary compatible with `1.0.x`.
There will be a `1.0.x` branch for releases that should stay binary
compatible (like the version bundled in the Scala 2.11 distribution).
Merge pull request #42 from gourlaysama/bump-version

Bump version to 1.1.0-SNAPSHOT