Tpool polishing

There were a handful of things about the tpool which were incorrect. I have fixed them. I have also combined much of the code that was redundant between the consensus package and the tpool package. A minor amount of testing was added, but most of this code is not tested. It'll make more sense to test it once the host and wallet packages have been built out a bit more.

A lot of the locking complexity has been minimized. The lock is still pretty complex, but it's less complex.