Minor tweaks

A couple of minor commits:

* `spock-0.6-SNAPSHOT` can't be found in any of the standard grails repos, so bumped it to 0.6 instead.
* Added `pluginConfig` to `dependsOn` list. We had a situation where another plugin was loading after freemarker plugin that also required pluginConfig. This was causing pluginConfig to load **after** freemarker, which was causing all kinds of crazy errors.