Add tagged logging to SoftwareAgent
Change scope of logger in SoftwareAgent

Turn @@logger into module constant Logger.

Besides making Rubocop happy, this expresses more what I'd originally
meant:  that all SoftwareAgents should share one logger.
Update rubocop to ignore Vagrantfile and Guardfile
Merge pull request #42 from dpla/rubocop-update

Update rubocop to ignore Vagrantfile and Guardfile
Merge pull request #41 from dpla/feature/tagged-logging

Add tagged logging to SoftwareAgent
Move files from app/models to lib

- Move classes and modules that are not model-like (that don't do
  persistence) into lib.
- Update autoloading in the engine's bootstrapping as a result of this
- Clean up some autoload statements in krikri.rb as a result of the
  autoloading changes.