deposit: plupload improvements

* Allows autoupload on file selected.

* Fixes a bug when deleting a file right after uploading it.

* Fix in Blueprint url endpoints for upload urls.

Signed-off-by: Javier Martin Montull <javier.martin.montull@cern.ch>
sqlalchemy: addition of Encrypted type

* Adds a custom type which is called `Encrypted`. It uses
  the AES algorithm provided by pycrypto in order to encrypt and
  decrypt.

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>