Avoid segfaults from reading old results messages.
Check that parrot's p->break_address is valid.

For some reason, p->break_address sometimes points outside valid memory maps.
This causes execve to try to execute invalid filenames, generating "Bad
address" errors. Until we figure out why that is, now we check if the address
is valid, and if not, then we find the arguments scratch space with the
fallback function.
Merge branch 'master' of github.com:cooperative-computing-lab/cctools
Report whether break is valid only when debugging.
Merge branch 'master' of github.com:cooperative-computing-lab/cctools
Instead of disconnecting a worker that sends an unidentified results message,
ignore the message and soak the result's standard output

This is for when a worker has been reset but had already sent a result message
to the master (usually a foreman).
Have worker disconnect from master instead of aborting when simulating volatility.