Added drag/drop file support removed FF22 paste

* Removed duplicate functionality from HomeModule.cs
  to ensure only one upload method
* Added drag/drop functionality to the ui
* Removed Firefox paste handling code
* Cleaned up file upload js to remove code duplication

![Drag/Drop UI](https://jabbr.blob.core.windows.net/jabbr-uploads/clipboard_db382a974ddd4f1abe6f32d48e326f39_012f.png)