[SQUASH ME] pr_check: don't stop script on error
[SQUASH ME] pr_check: correct color output
[SQUASH ME] pr_check: functionize label checks
[SQUASH ME] pr_check: base log on merge-base not upstream's master ref
[SQUASH ME] pr_check: make script easier to read
[SQUASH ME] pr_check: Utilize some git magic for cool output