Changes to be compatible with Grails 2.4

Hi,
I'd like to commit few small changes in order to make plugin compatible with Grails 2.4.x:
- FileUploaderService : ConfigurationHolder is replaced by grails.util.Holder.config
- FileUploaderGrailsPlugin : dependsOn = ["hibernate4":"4.3 > *"]
- FileUploaderController : no more println (nothing to do with 2.4 but would be appreciable ;p) 
- application.properties : updated to grails 2.4.4 (and no more plugins declaration)
Thanks, Vincent.