Use Guard with Hydra and get super-parallel test execution! Awesome!

Options:

* `:runner_log`: The location of the runner log where output is printed
* `:clear_runner_log`: Remove the runner log before each run
* `:show_runner_log`: Show the runner log after each run
* `:hydra_config`: The location of your Hydra config file
* `:test_matchers`: What glob would match the kind of tests you want to run
* `:all_on_start`: Run all tests when starting Guard