utils: LazyDict delitem support

* Adds support for removing items from a LazyDict.

* Fixes PEP8 errors.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
deposit: simple record tests

* Adds initial tests of simple record deposition type.

* Changes deposition registry to allow manual registration of
  deposition types.

* Adds feature to refresh an applications URL map in case deposition
  types are registered manually.

* Adds deposition test case helper class for easier unit testing of
  deposition types.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
deposit: fields deprecation

* Adds deprecation warnings to fields that are data model specific
  (e.g. title field) instead of input type specific (text field).
  These fields will be removed in the near future.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>
jsonalchemy: failing test fix

* Fixes failing test cases which was due to side effects introduced
  in 0a7ab631883fe514a28116fbc7fb8b47bd5c1bb4.

* Fixes PEP8 errors.

Signed-off-by: Lars Holm Nielsen <lars.holm.nielsen@cern.ch>