Description of problem: Currently it's not possible to link/unlink default components related to a test plan. Please provide a new TestPlan property components which would support add() and remove() methods.
PlanComponents container implemented https://github.com/psss/python-nitrate/commit/d3e8324dcdcce54431f74d5322c932ae1f7fba32 Note that the functionality is for now blocked by BZ#866974. Hopefully we get this implemented on the server side soon.