Standardize handling of glyph names for U. F. O. output.

This adds a standards-compliant name mangler and a hash table look-up for glyph names (so that we can iterate names that collide after mangling).

Hi, @JoesCat. It would indeed be desirable to accommodate people who are not using git. Is there an easy way to do this for gnulib? And what's the best way to do this for uthash?