Complete the parser and assorted fixes

With this come subtest and "skip all" parsing support as well as the removal of some taskell tasks and fixing tests marked as Todo.

Beware: I added a new test for the parser and since the parser is event-based, the test module contains Public Sub event handlers. These are currently picked up by gb.test as test methods, which is not desirable. Until we figure out how to solve this, I have marked tests in TInternals which are failing because of this as Todo.