- remove the duplicate detection logic from CompositeParser
  (this solves the strange infinite loop caused by the dart grammar)
- cleanup some of the matching code (while trying 
  to hunt down the dart remove-duplicate bug)
- disable the source paring tests for dart, they mostly fail
- update comments of CompositeParser2
- added two tests detecting the problem in parser iterator
- fixed the iterator to be super careful not to visit the same parser twice
- cleanup test code
- CompositeParser should not be settable
- version 0.4.1
Add hop_runner