Better exception handling/logging

[tonyc]

There's a few things going on in this commit.

The first was to refactor the fetchers to use a connection() method to make everything a bit easier to test.

The other is to specify the exception caught, and to log the error and backtrace to either the provided logger, Rails.logger (if it's there), or a stdlib Logger object.

[tonyc]

Just queued up another pull request for when I get to it

[UnConundrum]

I'd like to 2nd this request. I'm currently stuck in a loop somewhere, and having a heck of a time finding out where. There is no email to be processed to my knowledge, but fetcher seems to be pulling emails previously processed.... I can't find them either....