Also install build-tool

As of rev 22 it must be installed separately, and must be specified by version. Not sure of a better way to do this
[FIXED JENKINS-17997] Accept licences when installing SDK components.
[FIXED JENKINS-18015] Handle SDK detection with new 'build-tools' component.
Install Android SDK 22.0.1 by default.
Automatically install the m2 repositories for Gradle builds.
Fix apparent incorrect use of EqualsBuilder.