add: default metamethods has been added.
change: kqueue.c renamed to lkqueue.c.
add: lkqueue.h has been added.
add: helper macros has been added.
add: tostring_mt api for common metamethods has been added.
add: loop.c has been added.
change: metaname LKQ_LOOP has been renamed to LKQ_MT_LOOP.
add: loop method stop has been added.