Bug 691177 - Allow marking build or test platforms as not being part of 'all' on try pushes. r=bhearsum
Bug 691177 - Compute expected values for tests instead of hardcoding them. r=bhearsum

Although hardcoding is simpler, it makes it more difficult to update the tests. Plus, I may be changing the prettyName format dramatically soonish, and that would just be a pain with the current setup.
Bug 691177 - Basic set of tests for try-by-default=False. r=bhearsum
Bug 691177 - Make the try-nondefault marker on slave platform names work. r=bhearsum