(For the SLOW_PWM_HEATERS option)

Updated pins reference and servo support.

cross referenced between Rambo 1.1, 1.2, and 1.3

406*406 pixels

For cartesian bots, the X_AXIS is the real X movement and same for
Y_AXIS.
But for corexy bots, that is not true. The "X_AXIS" and "Y_AXIS" motors
(that should be named to A_AXIS
and B_AXIS) cannot be used for X and Y length, because A=X+Y and B=X-Y.
So we need to create other 2 "AXIS", named X_HEAD and Y_HEAD, meaning
the real displacement of the Head.
Having the real displacement of the head, we can calculate the total
movement length and apply the desired speed.

There is the possibility of turn on this features adding "#define SLOW_PWM_HEATERS" in Configuration.h

moved new COPYING file to top-level directory to make it more visible and remove clutter from Marlin subduer

This reverts commit dd7e4ee97f.

This reverts commit 2b9722f387.

try, try again.

If 'OK' is garbled on sending PC won't receive it.  Both machines will
wait on each other forever.  This resends OK if nothing is heard from PC
for a while to avoid this bad case.

Borrow code from https://github.com/arduino/Arduino/issues/1793

The compiler does not support comparing float values: "error: floating constant in preprocessor expression"
The loss in X/Y precision shouldn't matter for Z probes, as most microswitches or inductive sensors are larger than 1mm square anyway.

The compiler does not support comparing float values: "error: floating constant in preprocessor expression"
The loss in X/Y precision shouldn't matter for Z probes, as most microswitches or inductive sensors are larger than 1mm square anyway.

Somehow the pin definitions for the MAX6675 Slave Select/Chip Select got changed back to the hardware SPI SS/CS.  
Pin 49 cannot be used as that is used by the SD card socket to detect if an SD card is present.
Pin 53 is the Hardware SPI SS, which is dedicated, nicely, to the SD card SS and therefore cannot be used as the MAX6675 SS
Pin 66 is in Aux2 port adjacent to the Hardware SPI interface port on RAMPS 1.4, and is currently not used for anything.

This fixes two regressions, caused by #1167 and #1191 .

sp=space-padded, similar to: ns=no-sign