abcde: modernize + head added

@mikemcquaid I’d like to, but I really don’t know how to do that. I can’t even install `abcde` because it depends on `cd-discid`, which itself uses a patch from `trac.macports.org`, which is down at the moment ([they’re aware of that](https://twitter.com/macports/status/546710316315590656)). I just found it supports a [`-v` option](http://git.einval.com/cgi-bin/gitweb.cgi?p=abcde.git;a=blob;f=abcde.1;h=90929429025660d0b6ea1713c7cd4ca31436239d;hb=HEAD#l173) for the version, and added a test for that.