First stab at adding ngrep

I'm not sure what to call the licence; it seems to be the BSD licence
with a few clauses about attribution added (which I *think* we're
complying with)

This has only been tested on Yosemite.

I'm guessing this will need some tweaking (the name of the license at least) before it can land.
Done.

I checked for other ports that mentioned a BSD-like license; I found that simplejson uses "BSD like" while supervisor uses "BSD Like". Since there's not enough data to find a pattern, I picked one at random :)