verbosity, cleanup etc.

I think we can now safely close https://github.com/lualatex/luaotfload/issues/33,https://github.com/lualatex/luaotfload/issues/41, https://github.com/lualatex/luaotfload/issues/31, https://github.com/lualatex/luaotfload/issues/34 .