(- fix) More robust commit-label parsing, Unicode

Note: at the moment, the embedded regex doesn't separately capture the label-parameter, from the label itself. Theoretically, that can be left to the regex engine, saving manual splitting thereafter.

That's left as an exercise for the reader. ;)
(- doc) Adding an explanation (+ link) for labels

(Forgive my plugging of my own standard! ;)
Merge pull request #8 from ELLIOTTCABLE/patch-1

More robust commit-label parsing, and Unicode support in labels