Remove 'fileutils' requirement

Only one function uses fileutils.lua, not necessary to load the file
Better error messages running 'qa' on sp
Update for Lua 5.2 + new LuaTeX version

Lua 5.2 has table.unpack instead of unpack and fmod instead of mod

New LuaTeX version has .command instead of .cmd on pdf_colorstack
New Rakefile for new versions of LuaTeX/windows

We now support 64 bit windows!
Reading files on windows with binary mode on

I had a problem reading a font on windows without binary mode. So
I've switched all io.open() calls to "*b". I don't know of any
side effects.