Add the ability to drag and drop torrent files into webui

[Hazard]

Please add the ability to drag and drop .torrent files into the webui, as an easier way to add torrent files into the webui.

As it stands now (in chrome anyways), nothing happens, and you have to go through the Add Button in the top right to add a file.

[Hazard]

Changed to 1.4, since it seems to coincide with the descriptions listed there (webui stuff)