allow pull requests from forks to pass test using anonymous Octokit calls if under the lower 60/hr GitHub API rate limit.  Added more helpful error messages
check client is using valid token or warn if nil begets anonymous Octokit client
dev-fork pull CI build if travis set these: ENV['TRAVIS_SECURE_ENV_VARS'] == 'false' && ENV['TRAVIS_PULL_REQUEST'] != 'false'
Merge pull request #18 from apelade/develop

Make CI work on pull requests from developer forks, provide messages about needed ENV vars