New instructions can be defined in the prep program. We don't check that the "unknown" instruction was actually defined. Just pass it through. Fixes ttx with Skia.ttf on the Mac OS X. Fixes https://github.com/behdad/fonttools/issues/21
New instructions can be defined in the prep program. We don't check that the "unknown" instruction was actually defined. Just pass it through. Fixes ttx with Skia.ttf on the Mac OS X. Fixes https://github.com/behdad/fonttools/issues/21