Fixes #84

Rearchitects most of the IPAM logic to utilize much smaller locks, as
well as no superfluous iterative querying while an UPDATE lock is
active. After extensive testing with the suite that produced the
deadlocks earlier, we see no more deadlocks, and in fact the lock-step
mechnanism introduced seems to be working quite well so far.

Additionally, some tests were removed that no longer made sense, and
others were added to bring IPAM coverage back to 100%