WIP: Try rubocop

Rubocop was discussed a bit a while back.  I thought I'd give it a shot.  This is a WIP trying to figure out what checks to enable/disable and whether or not we want to use it.

Feedback wanted.
This is the `SpaceAroundEqualsInParameterDefault` cop.  Honestly, I could go either way; I configured it to the way that required fewer changes to conform.  We had more places that use no spaces than places that used spaces.