fontforge update for python

I found that configure didn't find the python.pc files using pkg-config without explicitly updating the PKG_CONFIG_PATH from the brew file. Sorry if this the incorrect way of going about this, no amount of adding depends_on 'python' was letting brew include python into the PKG_CONFIG_PATH.
It shouldn't be looking at `/usr/local/python` and any Python version installed there should be 2.7 anyway? Seems we need to debug their buildsystem a bit here. For what it's worth `depends_on :python` ensures 2.7 is being used anyway.