Logging Support

This is a major feature and focus of Jamie, namely having per-instance log files and the ability to change log levels throughout the system, including remotely running instances.

Another goal for Jamie is concurrent execution of instances which makes good logging vital. It is no longer enough to assume that all logging will be dumped to `STDOUT` in execution order.

The current strategy is to pull in [Logger](http://www.ruby-doc.org/stdlib-1.9.3/libdoc/logger/rdoc/Logger.html) from *stdlib* until it is outgrown or a feature in [Logging](https://rubygems.org/gems/logging) becomes too compelling.