add stack utility lib
improve tack api
switch display list storage to tack_t
switch displaylist_t over to tack_t storage
fix bug in gl.c tack_t usage
migrate gl stack to tack_t
remove DEFAULT_DISPLAYLIST_CAPACITY define
define MAX in tack.c
fix up some tack.c types
fix incorrect tack_grow size
fix some display list tack conversion regressions
remove state.list.count
fix tack_set beyond the end not increasing len
update some implemented TODOs
add tack_clear so display lists don't leak calls
fix tack_set off-by-one
add mock_assert
add glNewList() test
fix memory leak in glEndList
free if you call glNewList twice without glEndList