Add runners for live and test environments

This adds a `Runner`, `QsRunner` and `TestRunner`. This provides
a live runner, a test runner and the common logic between them.
The runner, in both live and test environments, is responsible
for building a handler class and running it appropriately. This
is part of working with the handler pattern and allows also
unit testing handlers without having to know Qs implementation
details.
Merge pull request #29 from redding/jcr-runner

Add runners for live and test environments