Marlin for Printrboard Updated

I just synced my Marlin branch for Printrboard with the latest code from ErikZalm’s branch. I noticed that there were a lot of changes in the planner, temperature control, etc.  Hopefully, it will be an improvement, rather than breaking anything.  Please report here or on github if you find any anolmalies with the new code.

Download Marlin for Printrboard here: https://github.com/lincomatic/Marlin