add default values for env variables PYRO_LOGLEVEL, PYRO_SERVERTYPE, PYRO_DETAILED_TRACEBACK
change os.environ.get to os.getenv
remove duplicate Pyro import
Merge pull request #132 from bcdarwin/env_defaults

add default values for Pyro env variables
Merge branch 'origin/develop' into torque_dependencies

Conflicts:
	pydpiper/pipeline.py
	pydpiper/pipeline_executor.py