Test case for exclusions in Gaze.

@shama, Testcase!

This is related to gruntjs/grunt-contrib-watch#20, will allow us to change the task to pass the unexpanded Globs to Gaze.

Assuming this is accepted, I'm pretty close to getting it fixed. I've got the exclusion test itself working, but it ends up being too greedy, and fires add events from Gaze on the .txt file.. etc. Not sure what's going on there yet.