Added HEATERS_PARALLEL (Request from reifsnyderb)
This allows a hot end with two heaters and a FET for each heater. This is useful if the FET is not capable of heating two heaters.
Changed slow buttons behavior.
Added new board for those of us with sanguinololu boards with ceramic resonators
Allow heaters to stay full On when PWM=127

In previous version, even with PWM = 127, the system turns the FET off
and then on in the next cycle. This bevavior may increase the FET heat
dissipation.
It was fixed keeping the FET always On when PWM=127.
Z Axis Safe Homing when using Z Probe

Recommended for those who are using the Z Probe for Z Homing (as
Z-Endstop)

This feature has two changes:

1) Allow user to choose where the Z Probe will touch the bed when homing
all axis together (G28) by setting below defines:

Z_SAFE_HOMING_X_POINT
Z_SAFE_HOMING_Y_POINT

2) Prevents the user to perform Z Axis Homing when the Z Probe is
outsite bed.
Bed Heater monitoring in Controller Fan

In some cases the Bed Heater FET heats up more then stepper drivers, so
this change add the bed monitoring to the controller fan. As soon as the
bed heater is turned on, the controller fan will run as well.
Fixed the plane vector equation to a simpler one (only dependent on the normal)

Removed the calculation of the inverse matrix since the rotation matrix is orthogonal, therefore inverted == transposed.
Much simpler and mathematically robust.
Implemented a least squares fit of the bed equation for auto bed leveling.

The code for the LSQ solver (qr_solve) is copyrighted by John Burkardt and released under LGPL here:
http://people.sc.fsu.edu/~%20jburkardt/c_src/qr_solve/qr_solve.html
(see qr_solve.cpp for further copyright information)
Added support for Cheaptronic v1 electronic
Merge pull request #675 from forrestg/master

Added support for Cheaptronic v1 electronic
Made numbering of heat bed thermistor more logical as D8 is bed, D9 is Extruder 2 and D10 is Extruder 1, so T0 should be E1, T1 E1 and T2 bed to be sequential as MOSFET-Outputs
Added posibility to set ENCODER_STEPS_PER_MENU_ITEM in Configuration.h like ENCODER_PULSES_PER_STEP as it depends on it for usability
Incorporate PS_DEFAULT_OFF for starting state on LCD menu entry
Minor code and comment polishing
Z and Y dual stepper drivers error

if you try to enable Z_DUAL_STEPPER_DRIVERS the error "You cannot have dual drivers for both Y and Z" shows even if you don't have defined Y_DUAL_STEPPER_DRIVERS and don't let you compile the firmware

to solve this problem i change this line:

#ifdef Z_DUAL_STEPPER_DRIVERS && Y_DUAL_STEPPER_DRIVERS

to:

#if defined (Z_DUAL_STEPPER_DRIVERS) && defined (Y_DUAL_STEPPER_DRIVERS)

now the error only show if you define both Z_DUAL_STEPPER_DRIVERS and Y_DUAL_STEPPER_DRIVERS
Merge pull request #677 from RicardoGA/patch-1

Z and Y dual stepper drivers error
Accurate bed leveling: x loop inside y and zigzag motion
Fixed planner bug
Merge pull request #657 from hcker2000/patch-1

Added new board
Revert "Made numbering of heat bed thermistor more logical as D8 is bed, D9 is Extruder 2 and D10 is Extruder 1, so T0 should be E1, T1 E1 and T2 bed to be sequential as MOSFET-Outputs"

This reverts commit b7eadb9f37971a9a2cb0b55a3cca0d013d4e6351.