Add .cordova directory creation to build tasks buildTree function.
Add .cordova directory creation to build tasks buildTree function.

Fixes the issue on iOS, where nothing get's copied to .cordova directory if it's not first created like other directories.
adriancmiranda/grunt-cordova,zipscene/grunt-phonegap,johnhornsby/grunt-phonegap,simonoff/grunt-phonegap,standup75/grunt-phonegap,optikalefx/grunt-phonegap,logankoester/grunt-phonegap,streamlinesocial/grunt-phonegap