Clean up logging

The test run should not output anything except that which is written by the reporter (e.g. pioneerformat.js, Cucumber JSON reporter, etc.). Currently, pioneer writes some information about the config file as well as test timing, which gets in the way when you want to pipe the result of a reporter into a file, for example.

I've moved the duration reporting inside the pioneerformat file, and only write the config file information when a verbose flag is set.