add functions for retrieving information about loaded fonts
add unsafe glyph checker
fix behavior of ``aux.slot_of_name()`` for missing glyphs

spotted by Robert
add script to extract parts of ``char-def.lua``
add serialization spec
create make rule combining glyphlist and character list generation
update NEWS
load character data on demand
add ``get_quad()``
Merge pull request #77 from phi-gamma/master

address Robert’s feature request concerning ``\letterspacefont``