Added PausingDeferredQueue class
Added tests for PausingDeferredQueue class
Removed unnecessary assert
Documented return value for putting object in PausingDeferredQueue
Separate out tests for PausingDeferredQueue
Correct description on docstring for PausingDeferredQueue's put
Improved docstrings for PausingDeferredQueue tests
Added links to docstrings for PausingDeferredQueue tests
Moved test setUp into individual tests for PausingDeferredQueue tests
Merge branch 'feature/issue-25-add-custom-deferredqueue' into develop