Adding object mapping in .using()

Hello eford, 

Please review the following commits I made in branch 'azulus-objectMap'.

4bdaff4910a8aeb9fb626faf1a7ab7250fe97619 (2013-03-18 13:15:19 -0700)
Adding object mapping in shepherd

ae7db1f762886231b52136847a19e370b61bf9c1 (2013-03-18 10:30:45 -0700)
Refactored tests to remove {_literal:''} syntax

R=eford