Adapt daf_butlerUtils to py3
Port obs_subaru to Python 3
Port obs_monocam to Python 3
Jenkins is checking py2 and py3.
I'm dead in the water right now due to computer power cable problems.
I've had a look at the PR as it currently stands. One comment regarding number.Integral.
Tim Jenness has reviewed. This has passed Jenkins with py2 and py3. Merged to master.