Updates Hangprinter support

[tobbelobb]

Hi, I just rebased my code that I run in the simulator onto 3.7-dev. In this PR I've extracted HangprinterKinematics.{h,cpp} from my RRF fork and made it compile nicely with your upstream 3.7-dev branch in the various involved repos.

It includes

 - Adds the missing Hangprinter registration so M669 K6 maps to a real kinematics.
 - Implements new flex compensation for Hangprinter
 - Hangprinter: new quadratic forward transform
 - Hangprinter: all anchors drives control of all moves
 - Hangprinter: Removes the M669 K-anchor to avoid name clash
 - Hangprinter: allow board address up to 49.0

See it running in the simulator at https://tobbelobb.github.io/hp-sim5/hp-sim-3d/

[tobbelobb]

Added the commit that allows one force for each motor, like M569.4 P40.0:41.0:42.0:43.0 T1.0:2.2:0:11.

I have two other features that I've ommitted here. Tell me if you want them.

• The RRF_HOST_BUILD for a x86 version of ReprapFirmware.
• Caching driver directions that gets sent to remote drivers upon M569 S.... Without this (or a way to ask the remote driver) we need to hard-code motor directions in HangprinterKinematics.cpp. I included a small hard-coding patch in this PR's HangprinterKinematics.cpp, so we can avoid the direction caching if you don't want it now.