Added interpolation of glyph advance width, from HVAR/hmtx, and derivation of new LSB.
Updated tests to match.
Needed to cherrypick from another branch an update for psCharstrings to allow the CFFSubr.draw() method to work.
varStore.py. Commit the correct function references.
psCharstrings.py. Add decompiler class specifically for flattening subroutinized charstrings.
mutator.py. Flatten the subroutinized charstrings, delete the Subrs.
TestCFF2VF.otf, Updated to version with subroutinization. Updated expected ttx output.