Provide a banal 'paste' postmessage implementation.

Browsers will allow apps to populate the clipboard, but not read
from it without user input. This patch makes it possible for
context menus with 'Paste' in them to trigger a real OS paste
when hosted inside the webview.

Signed-off-by: Michael Meeks <michael.meeks@collabora.com>

Using URL's returned from the server for sharing

Doing this so the app makes use of pretty URL's without index.php

Signed-off-by: Jamie White <jamie@consolegfx.net>