Merge pull request #106 from sbesson/api_status

Add a new CheckStatus command to retrieve Github API status
Merge pull request #107 from sbesson/status_improvements

Add additional choices in --check-commit-status
Add failing test for mismatching PRs check
Fix mismatching PRs count
Fix integration tests to test mismatch PRs check and --no-check option
merge master -D org -I include -E exclude: PR 108 (Improve scc unrebased-prs output)