Update ThemeTagLib.groovy

http://jira.grails.org/browse/GPPLATUI-31
Changed method debugMode to a different name.
Merge pull request #3 from neilsimms/master

#GPPLATUI-31 - The debug output is showing up in the generated pages even though my application does not call <theme:debugMode/>
Merge branches '1.0.RC5' and 'master' of github.com:MerryCoders/grails-platform-ui into 1.0.RC5