Documentation and Move the code into it's own sub-folder for Arduino

[drf5n]

It would be nice to have the code be in it's own fumik_rv9 subfolder like: fumik_rv9/fumik_rv9.ino so Arduino doesn't complain and move it.

It would also be nice to see a diagram identifying the triangles, angles and constants in https://github.com/fumikrobot/source-code/blob/cf6d6d794c014ce6a81f114d8591082b22c6cf37/fumik_rv9.ino#L315 As is, it looks very difficult to calibrate to a new installation. Is https://github.com/fumikrobot/source-code/blob/cf6d6d794c014ce6a81f114d8591082b22c6cf37/fumik_rv9.ino#L324 the distance between the anchors?

Cool project, thanks.