Plugin release sanity checks

These tests should be applied to the respective ranges of Grails, Spock and the plugin versions:

• Build and test the plugin with grails clean; grails refresh-dependencies; grails compile; grails test-app
• Run grails maven-install to make the new plugin version available in your local Maven directory
• Create a new hello app
• Modify the BuildConfig.groovy adding the plugin with compile scope to the "plugins" closure (i.e. compile ':jaxrs:$VERSION')
• Run grails refresh-dependencies
• Create a simple reasource with grails create-resource test
• Run the app and browse to the resource path (as per the GettingStarted examples in wiki)