No need to change this right now, but there's a cleaner way to check for binary files that doesn't depend on file extension. Basically, you look at the first N-bytes (where N is like 256 or something) and if there are any '\0' characters, it's almost certainly binary. Because almost all binary files end up with some zeros but text files do NOT have zeros, it works really well.

Anyway, I think an extension list is OK for now, but maybe we should look at changing it in the sprint after next to be a little more heuristic.