* lily/ttf.cc (print_trailer): if all else fails: use

* lily/ttf.cc (print_trailer): if all else fails: use
glyphIndexXXXX as glyph name.

* lily/pango-font.cc (pango_item_string_stencil): only use cmap
entry if cmap contains glyph.
(get_index_to_charcode_map): remove from Pango_font class, use
global filename -> font mapping.
(get_glyph_index_name): new function.
(pango_item_string_stencil): use glyphIndexXXXX as glyph name,
only for TTF.