Pumpoffsets

A nice cleanup to how we're writing the DCPump speed to the channels. This should make a lot of things much easier. I also added a DCPump.AntiSyncOffset so that you could change the power level on the secondary pump. I'm putting the pull request in despite it not being tested yet, because the cleanup alone is worth it and the offset code I've been using the same formulation for a while, so I'm pretty confident. This passes the compile test though :)