G03 Full circle did not work (G02 is working correct)

Corrected retract() call for use of auto probe without sled enabled.

Fix build for non-sled bed auto levelling

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

Fix issue 935: error in matrix calculation

thanks...

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

Implemented SCARA-Maths

Fix lcd itostr3() to handle negative numbers

Leapfrog controller board support

temperature.cpp fixes for SD card and MAX6675

FWRETRACT fixes

With option DISABLE_INACTIVE_EXTRUDER the extruder is disable to early

Adding Z Probe via sled mounted endstop

Z probe repeatability with correct defaults

Fix reseting CHDK pin to LOW

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

Fix for a wrong checksum truncation for certain commands

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.

Implementation of FW extruder change retract

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.

Update my github

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

Changed the declaration of the variable "cancel_heatup" to Marlin_main.cpp to fix issue on commit #965

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.

Fixed stop print LCD function on M104