Added support for an optional serializer.
Added documentation about the serializer option.

Added documentation about the serializer option.
Update README.rst

Fixed typo.
Fixes bug when there is no element to deserialize (pop timeout) => Check that the item exists before deserializing.
Merge branch 'serializer_support' of git://github.com/YAmikep/saferedisqueue into YAmikep-serializer_support

Also added some tests and documentation.

* 'serializer_support' of git://github.com/YAmikep/saferedisqueue:
  Fixes bug when there is no element to deserialize (pop timeout) => Check that the item exists before deserializing.
  Update README.rst
  Added documentation about the serializer option.
  Added support for an optional serializer.

Conflicts:
	test_saferedisqueue.py