Converted JSONObject usage to Gson, which does a better job at parsing/converting to JSON. Also added patch for better previews, props kokejb

Ref: http://dev.android.wordpress.org/2013/02/15/while-testing-kokejbs-preview-patch-this-week-i/

git-svn-id: https://android.svn.wordpress.org/trunk@903 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0