Replace use of whitelist/blacklist with trigger/ignore (#196)
Users can now specify trigger and ignore instead of whitelist
and blacklist in their configuration options, respectively.
The blacklist and whitelist options are deprecated and will
be removed in a future release.
Account for special GitHub behavior with Travis CI (#194)
Travis CI status checks are apparently special-cased in GitHub code for
protected branches such that they behave differently from all other
checks. To allow Bulldozer to work for users of Travis CI Enterprise,
implement a matching special case in Bulldozer.