Updated gradle to 1.11

This needed a bit of a change to the dependencies of the entity scanner, it appears that because the reflection library uses guava, we run into this Gradle bug if we upgrade beyond 1.8: http://issues.gradle.org/browse/GRADLE-2962.  Specifying the same version of guava as the one Gradle uses gets around this problem.  It does mean changing some of our dependencies though. The bug appears to have been fixed in gradle 1.12, so we could wait until that's out.