examples/.*c: Pass NULL to akl_init_state()'s second param
src/aklisp.c: Add akl_frame_restore()
src/aklisp.c: akl_frame_init() cleanups
vector.c: Add akl_vector_truncate_by()
util.c: Rearrange if syntax
aklisp.c: Workaround frame handling and akl_frame_init()
gc.c: Delete unused AKL_CPY_MEM_CALLBACK()
lib.c: Don't return NULL on normal runs in lib functions
Merge branch 'wip' of https://github.com/akoskovacs/AkLisp into wip