Various fixes to test_debugger.py

- Made it possible to run under Python Unit Test run in PyDev
- Refactored to have base class (mixin) that has the tests and
  subclasses for each target (Python/Jython)
- Added IronPython debugger targets
- Fixed _debugger_case1.py for Jython + IronPython (gc.get_referrers)
- Use TestDependent entry for PYTHON_EXE instead of 'python' on path
- Use sockets to get a free port (in UpdatePort)

Note that some IronPython tests fail and still need a review.
Run custom commands/python code in the context of the debugger

This is a new debug command (127) called RunCustomOperationCommand.
Update test_with_tycho.patch
Merge branch 'actions_on_variables' of https://github.com/jonahkichwacoders/Pydev into jonahkichwacoders-actions_on_variables
Integrated code to execute custom command on variable (by Jonah). Also, by default a pprint is integrated with this feature.