add align target to Duktape.env
move object property realloc ptr setup to duk_hobject.h layout macros so that it's easier to maintain
add a selftest for duk_hbuffer_fixed sizeof
rename object LAYOUT_2 to LAYOUT_3 to make space for a less modified version of LAYOUT_1, add a portable align trick to duk_hbuffer_fixed which doesn't increase struct size unnecessarily, rename ALIGN4/8 to ALIGN_4/ALIGN_8
add hobject layout 2 which is layout 1 but: (1) key and entry order reversed to avoid aligning entries, (2) padding bytes between flags and array entries
Merge branch 'align-rework'