Wip on dropper and gravity editor directives
ImageCropper Added as a real property editor + polish

Polishing the UI, it can now edit actual image data and store crop
points / center point as json, next add configuration service
Fixes issue with MediaHelper and complex property values
Improved caching in debug mode by adding global yepnope filter
Adds cache bursting to production mode

Package installer bumps CDF version, we make sure to purge the angular
cache
initial js loader gets a cache burst as well
Merge remote-tracking branch 'origin/7.1.0-ImageCropper-WIP' into 7.1.0