Filepicker

This adds an app to use the filepicker.io file uploader
It is off by default, but can be enabled by a settings change and providing an API key

Also included are two bug fixes:
 - the upload auth decorator didn't check the cookie for the session id, it now does
 - the datafile list first load behaved differently, due to it being loaded by an include on the server. now it always loads via ajax