For some reason, "getCustomTypefaceForFont" wasn't being called on OS X.
It probably has something to do with platform-specific code for loading
fonts. Now, in cases where custom fonts are needed, loading requires
4 lines instead of 1. Kind of a pain, so hopefully this is a temporary
solution until we can figure out what's different about Macs.

It's unused, declared obsolete, and is triggering GCC warnings. If
anyone wants it back, it'll be in the Git history.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>