This is the bulk of the work for recording the resource pointer with
with builtin data. I don't know how much of a difference it makes for
most things, but it's probably pretty big for qwaq-curses due to the
very high number of calls to the curses builtins.
Closes#26
They are both gone, and pr_pointer_t is now pr_ptr_t (pointer may be a
little clearer than ptr, but ptr is consistent with things like intptr,
and keeps the type name short).
And create rua_game to coordinate other game builtins.
Menus are broken for key handling, but have been since the input rewrite
anyway. rua_input adds the ability to create buttons and axes (but not
destroy them). More work needs to be done to flesh things out, though.
