This function should only be used with sled, not all bed auto
levelling.

	modified:   Marlin/Configuration.h
	modified:   Marlin/pins.h

Adjusted the  #define PID_dT to reflect 10 A to D sample steps, vs
original 8.

The serial protocol has to stay machine readable, without having
to cope with a ton of different human language variants. So
just leave it at the original english version.

Should fix ErikZalm/Marlin#1052

This reverts commit 1d0fe035f3.

Update the config file for improvements and clarifying what diameter to
use in the slicer software.

Improvement to avoid reinitializing delay buffer with every print. Fixed
issues in buffer indexing and memory out of bounds due to floating point
imprecision.  Simplified the code by avoiding conversion to standard
diameter and 1cu mm extrusion, which caused complications in determining
mm extruded.

chdkActive was set to false regardless of (millis() - chdkHigh) being bigger than the CHDK_DELAY or not. So if (millis() - chdkHigh) wasn't bigger than the delay the first time, the CHDK would never be set back to LOW.

Also, don't return from the function, as there might be other stuff to do, after the CHDK check.

This snapshot has the Auto Bed Leveling turned off because most Marlin
users do not have that feature.

Z_PROBE_REPEATABILITY test for Auto Bed Leveling.
Implemented as M48 with extra user specified options.
Full support at
http://3dprintboard.com/showthread.php?2802-Auto_Bed_Leveling-Z-Probe-Repeatability-code

This feature allows the printer to read the filament diameter
automatically and adjust the printer in real time.  Added code to read
an analog voltage that represents a filament diameter measurement.  This
measurement is delayed in a ring buffer to compensate for sensors that
are a distance away from the extruder.  The measurement is used to
adjust the volumetric_multiplier for the extruder.  Some additional g
codes (M404, M405, M406, M407) are used to set parameters and turn
on/off the control. g code M221 is updated.  Pins for RAMPS1.4, RAMBO,
and Printrboard are identified for analog input.  The configuration file
is updated with relevant user parameters.

Original code is using WRITE from fastio, but original used pinMode to
set pin direction and did not use the fastio SET_INPUT or SET_OUTPUT.
This caused an issue with the rotary encoder interface to  boards based
on teensyduino, since for teensyduino pin numbers for fastio and the
usual Arduino IO are different.

Positioning of string terminator to truncate checksum from the commands
M23, M28, M30, M32, M928 and M117 was off by one, causing the last
letter of the actual command to be truncated instead of just the
checksum.

In case of the SD commands this caused checksummed commands targeting
existing files to fail since the last letter of the filename was
truncated.

In case of M117 this caused the last given letter not to be displayed.

This patch fixes the off-by-one error and sets the null terminator
on the exact position of the * starting the checksum instead of the
character before that.

This is a feature to protect your printer from burn up in flames if it
has a thermistor coming off place (this happened to a friend of mine
recently and motivated me writing this feature).

The issue: If a thermistor come off, it will read a lower temperature
than actual. The system will turn the heater on forever, burning up the
filament and anything
else around.

After the temperature reaches the target for the first time, this
feature will start measuring for how long the current temperature stays
below the target minus _HYSTERESIS (set_temperature -
THERMAL_RUNAWAY_PROTECTION_HYSTERESIS).

If it stays longer than _PERIOD, it means the thermistor temperature
cannot catch up with the target, so something *may be* wrong. Then, to
be on the safe side, the system will he halt.

Bear in mind the count down will just start AFTER the first time the
thermistor temperature is over the target, so you will have no problem
if your extruder heater takes 2 minutes to hit the target on heating.

Fixes #817

Enables both SD card and MAX6675 to talk with each other
Fixes also issue #750

I have added the pin set for the leapfrog and the support of dual Y and Z

Leapfrog added to the board list

Leapfrog board added to the pin list

This is a feature to protect your printer from burn up in flames if it
has a thermistor coming off place (this happened to a friend of mine
recently and motivated me writing this feature).

The issue: If a thermistor come off, it will read a lower temperature
than actual. The system will turn the heater on forever, burning up the
filament and anything
else around.

After the temperature reaches the target for the first time, this
feature will start measuring for how long the current temperature stays
below the target minus _HYSTERESIS (set_temperature -
THERMAL_RUNAWAY_PROTECTION_HYSTERESIS).

If it stays longer than _PERIOD, it means the thermistor temperature
cannot catch up with the target, so something *may be* wrong. Then, to
be on the safe side, the system will he halt.

Bear in mind the count down will just start AFTER the first time the
thermistor temperature is over the target, so you will have no problem
if your extruder heater takes 2 minutes to hit the target on heating.

sorry for that

This leads to the command not being acknowledged properly
by the firmware, leading to consecutive issues in host software
waiting for an acknowledgement.

FW retraction is extended onto swap retraction invoked by 'G10 S1'.
Bookkeeping of the retract state of all extruders allows for having one
extruder fw standard retracted while another extruder is swap retracted.
An LCD menu item for the swap retract and recover length was added.

Having the non-active feeder motors powered on all the time is not
necessary. A feature to deactivate the unused feeder motors has been
implemented. The feature is enabled on default but can be switched off
in the configuration.