Broke out paramiko.AuthenticationException; removed erroneous ':r' format_specs
Lots of insignificant formatting changes
Reworked exception handling to be clearer and more holistic; general clean-up

* Homogenized exceptions in services; moved logging from services to Platform
* Shifted bulk of the exception catching burden to Platform for greater context
* Added type check to credentials property in Platform to simplify other classes
* Moved iterable behavior out of Platform into the IterablePlatform subclass
* Updated LinuxPlatform to inherit IterablePlatform
* Changed existing docstrings to reStructuredText format
* Added/modified comments, docstrings
Merge pull request #3 from jeandesmorts/rework_exception_handling

Rework exception handling