Merge remote-tracking branch 'yipdw/python3' into python3/development

Conflicts:
	seesaw/__init__.py
Updates readme, requirements.txt, shebangs for Python 3.
More 2to3 fixes.
Updates travis config for Python 3.
Updates setup.py requirements.
Renames to run-pipeline3 for 2 and 3 coexistance.
Merge branch 'master' into python3/development

Conflicts:
	seesaw/__init__.py
Fixes unique_id_str() str'ing a bytes obj. Bumps Version 0.1.6b2.
Add on_cleanup event to pipeline.