add nested commit option

as per #9

this adds the nestedCommit option (defaults to on) which controls whether or not create urls are nested

Edit: its one of those days.. the changes for this feature should work without #11 but I have accidentally created this feature branch off my other instead of master and hence included both commits here.

Edit2: the travis builds fail because I locally edited the test suite to not use its own copy of the js files. Perhaps that should be addressed separately as to not store duplicate copies of the js files in the repo.