Added a hidden option to aid debugging pyheapdump itself
Rewrite of the locking system. The previous system caused
dead locks under certain conditions.

Added a synthetic example of a multi threaded application with
a crashing worker thread.
New API function dump_on_unhandled_exceptions.
This function can be used as a decorator or to install
a sys.excepthook handler.
make the test suite pydev friendly
Add an example how to globally activate pyheapdump