add PullRequest.parse_url (and test)
add tests for rejecting malformed urls
use an example open pr that should never get closed
refactoring: is_an_open_github_pr -> is_open; move valid pr params to spec helper file
refactor checking of pulls being real and open
Merge branch 'master' into 11-verify-pr-is-open

Conflicts:
	app/controllers/pull_requests_controller.rb
	app/models/pull_request.rb
combine github oauth and pr-checking