A couple of tiny fixes to make CID reading possible.
support for reading Type1 glyph order and extract unitsPerEm from /FontMatrix (big thanks to Miguel)
- check both lookupType and format before extracting a gpos subtable
- caretOffset is not required and not always set (fe in CID fonts)
Adding support for extracting ttx files

I know ttx is not a binary format but its nice to convert the data to a
font object
Merge pull request #1 from typemytype/master

Adding support for extracting ttx files
Pull Frederik's TTX format extension into this branch.