Add Object Range Request Tests

* added an object range request regression module.
* added docstrings
* added a less general exception catch
* refactored the parse msg method
* added a method to return the boundary from the content-type
  header
* refactored the tests to used the refactored helper methods

Change-Id: If66618fc06494f981211fd5344eed0123dff3417
Merge "Add Object Range Request Tests"