Add a comma before e.g.

This might be a point of contention in the style guide world.  Chicago Style guide (which I assume is related to Chicago Style Pizza aka Real Pizza so it has to be awesome) uses "eg," internally.  However, I now live in NYC which doesn't seem to have a style guide of it's own (much like it doesn't have real pizza of it's own) so I say screw it.  This matters to people besides me a lot more than it matters to me.  I care about pizza, not grammar.

I don't know grammar, but @helenhousandi and @varlese both so I should the comma and both are much better writers than I am.  The thing I'm best at writing is long rambling commit messages that may or may not contain too much information.  Well, that's not exactly true.  I can write other things pretty well, but for prose, I think I write commit messages the best.

Props @helenhousandi and @varlese