Updated Gradle version from 1.3 to 1.4.

Gradle 1.4 was released a few days ago. It has a few minor enhancements that I am taking advantage of that cause my build to fail on 1.3. Specifically, the automatic configuration of Scala dependency used by ScalaCompile and Scaladoc tasks: http://www.gradle.org/docs/current/release-notes#automatic-configuration-of-scala-dependency-used-by-scalacompile-and-scaladoc-tasks