fix coveralls check

Signed-off-by: Alex Suraci <asuraci@pivotallabs.com>
Signed-off-by: Chris Adams <cadams@pivotallabs.com>
don't stop processes through wsh

when a container runs out of memory, it's possible that wshd itself is paused,
and so stop.sh would just hang.

instead, we stop all processes from the outside by going over the container's
cgroup's list of tasks. every second we send TERM to all processes (except for
wshd), and after 10 seconds that increases to KILL.

we're careful to send the signals to all proceses in the container, not just
the parent's immediate children. added integration tests to ensure this case.

Signed-off-by: Chris Adams <cadams@pivotallabs.com>
bump deps

Signed-off-by: Chris Adams <cadams@pivotallabs.com>
remove debugging

Signed-off-by: Chris Adams <cadams@pivotallabs.com>
switch wshd tests to gexec/gbytes

Signed-off-by: Chris Adams <cadams@pivotallabs.com>