Release 1.3.0

See the 1.3.0 milestone for the full list of related tickets and PRs.

Enhancements

1. Cross publish to both sbt 0.13 and 1.x. #105, #106, #107 by @larsrh & @xuwei-k
2. Bump pamflet to version 0.7.1. #103 by @xuwei-k

Fixes

1. Fix the build in Travis. #104 by @ashawley

Using sbt-site with sbt version 1.0

This release adds support for sbt 1.0, however, the Laika and Paradox generators are only available for sbt 0.13.