I find that the PID routine works better when the cooling fan is switched on
at the beginning of a warm up routine.  Otherwise when you enable the fan
just before a print, you have a delay as the PIDre-adjusts.

This should also be safer as most cooling fans are directed at the hot -ends
thermal barrier!

Instead of a single pre-heat, now there is pre-heat ABS and PLA options
Added defines to the configuration file to adjust preheat temperatures for both

Updated the Xsteps ... settings via the LCD menu

Signed-off-by: Blair Thompson <mail@justblair.co.uk>

next try for manual axis movement

that pulls down the SDCARDDETECT pin and mimicking the pull and reinsert ofa a SD card

replace $ARDUINO_HOME/hardware/tools/avr/etc/arduino.conf with this file

Simplified stepper inactive time

Simplified stepper inactive time

if (millimeters_of_travel == 0.0) => if (millimeters_of_travel < 0.001)
(thanks mooselake)

One for common settings.
One for advanced settings.

Default off.

ON GEN7 there is no temperature reading when power is off.. so Marlin
would kill itself. There seems to be an update from "Traumflug" on GEN7
using standby VCC for thermistors.

- redo disable Beeper if PIN is set to -1

- Added support for ATMega1284

Needs some work to remove the blocking in read max6675.

Added late z enable. (blddk request)
Only calculate look ahead if >2 moves in buffer.
Removed some FORCE_INLINE to save memory.

Signed-off-by: Erik van der Zalm <erik@vdzalm.eu>