Prepared for release 0.7.

Removed SNAPSHOT from version number.
Upgraded to current Liquibase release.
Still on Groovy 1.8.6 due to a bug in groovydoc generation when using 2.0.4. I haven't chased this bug down yet.
Merge commit 'refs/pull/4/head' of github.com:tlberglund/gradle-liquibase-plugin
Release 0.7
Upgraded wrapper to 1.4
Release 0.7
Upgraded wrapper to 1.4
Merge tag '0.7'