test case
remove unneeded atomics
use only memory_order_seq_cst. attempt to fix race in array grow.
Merge branch 'master' into ws_sched

Conflicts:
	include/ten/work_deque.hh
fix potential rendez deadlock
don't put canceled or deadlined tasks to sleep
clean up channel impl
simplify channel logic. fix race condition in unbuffered mode.
Merge branch 'master' into ws_sched
silence warning