Started implementing squawk unit test

Squawk is more complicated to test than other payloads: flow can travel
in both directions, complicating test checking. It's not done yet, and
I'll probably have to upgrade the router payload test system to handle
IP addresses better.
Bypassed IP issue, still having a packet mismatch

Peck unit test is having trouble with a packet mismatch, even though IP
addresses work
Fixed payload mismatch

Forgot to copy squawk payload into serial structure
Added CK_NOFORK (commented out) for debugging

This is a check.h option; normall check forks tests, so that a segfault
doesn't bring down the entire test suite. This is not very good for
debugging, though, so there is an option to keep check.h from forking
off. I added it (commented out) for when I need to debug segfaults
Patched some memory leaks

routingTableDestroy had a pretty big one.
There still seems to be a leak in sgSerialReceive in sg_serial_stubs.c
Fixed an uninitialized warning from valgrind
Some work to squash that last valgrind blip

This should just be a problem in testing, but I just want to make sure
valgrind doesn't pop anything up