catch NoSuchProcess error in case of a race condition when killing a process - refs #637
make sure the arbiter is really stopped even if the test fails - refs #637
more fixing for #737
raising errors happening in co-routines
removed verbosity
print the full traceback to get more context
typo
we want -sv
use an env variable to re-raise async errors
make sure children() is called in a try...except NoSuchProcess loop - refs #737
removed -s and dont use randomize for 2.6
trying _emergency_stop to speed up tests