+ Removed most explicit pathnames, use the standard make "VPATH" to let
make find the files for itself.

+ Added a "hardware variant" variable that allows compiging Sanguino and
Gen7 as well as "generic" arduino.

+ Allows overriding the MOTHERBOARD define from the Makefile

+ Removed the 'preprocessor' bit that wasn't needed, now just "include" the
files that are needed, since it allows gcc to show the right file/line
when displaying error/warnings.

+ Uses gcc's own dependency generator to generate the .d files, and
and include these instead of self-patching the makefile

Signed-off-by: Michel Pollet <buserror@gmail.com>

One array was too short. This had nothing to do with long filenames, other than if they were 12 characters exactly, which could only happen if the extension and the text before were filled completely

Better pin configuration for rotary encoder in RAMPS boards

Make F_CPU dependence of stepper.cpp more explicit

M303 Starts autotune. Wait till the Kp Ki and Kd constants are printed.
Put these values in Configuration.h

While Waiting for hotbed to warm up via M190, LCD Display and Click Enco...

While Waiting for hotbed to warm up via M190, LCD Display and Click Encoder input freeze until target temperature is reached.

Changed Pin Assignment for the RAMPS motherboard so that LCD and Rotary encoder are all wired to AUX-4

This simplifies wiring for those with RAMPS 1.3 and 1.4 boards.

Translation still needed.

make analog2tempBed return a precise celsius reading for BED_USES_THERMISTOR, ...

Made plan_buffer_line arguments const...