Tests that check the full list of todo items are no longer order dependant

In order to reduce the number of failures for implementations that prepend rather than append items, the tests that check the full list of todo items are no longer order dependant. There is now a single test that checks this requirement:

'should append new items to the bottom of the list'
Merge pull request #803 from ColinEberhardt/remove-order-dependency

Tests that check the full list of todo items are no longer order dependant