Move python unit tests to test directory
Remove python test package
Rename test.sh to simple.sh
Remove test driver

This can be replaced with a simple:

python -m unittest discover
Refactor exitcode cluster record parser and tests
Change pegasus-config so it works in development
Minor output changes for exitcode functional tests
Make cluster test naming consistent with other tests
Update ant build for python unit tests
Turn exitcode into a module
Add message quoting to exitcode success/failure messages

Quoting means replacing ' ' with '+', and '+' '\+'
Exitcode now expects success and failure messages to be quoted because
of limitations in DAGMan, so it unquotes them.
Add PYTHONPATH to python unit tests