Add 4th extruder

Add 4th extruder

Add 4th extruder

All the additions look proper. I can't think of any other extruder-count-related items that you might have missed. So, with some optimism, I will merge this for testing.

Add PID_dT in temeprature.cpp

Proposed fix to #1379. Printrboard I2C LCD support

Pins 2 and 3 are probably general-use pins, since the filament sensor
uses pin 2.

Merge branch 'issue_1379_printrboard_lcd' of https://github.com/thinkyhead/Marlin into issue_1379_printrboard_lcd
Diverged from origin

Githun insert this line when i merge with actual Branch development...

Conflicts:
	Marlin/temperature.cpp

Borrow from Ultimaker to fix MAX6675 SPI conflict

Merge branch 'issue_1227_max6675_spi' of https://github.com/thinkyhead/Marlin into issue_1227_max6675_spi
Branches diverged

Changes to temperature.cpp from Ultimaker fork, intended to address
#1226 and #1227

Formatting cleanup of quiet sources

Show Custom M_Code for Z-Probe Offset when entering M503

Done

Fix Issue #1356 – remove EXTRUDER1_Z_OFFSET

This define is not used.

Changes to temperature.cpp from Ultimaker fork, intended to address
#1226 and #1227

Code wont compile with extruder but without bed runaway protection defined.

Without this fix, the code wont compile with extruder but without bed
runaway protection defined.

removed function step_wait() from stepper.cpp

Add: Board for Vellemann K8200 (derived from 3Drag)

Fixing a build error for melzi and gfx display

Add proper delay in stepper.cpp

removed function step_wait() from stepper.cpp because its used nowhere.

Issue #1385 describes a delay that the compiler is optimizing out and
this solution.

# Add: Example Configuration for Vellemann K8200 - based on new
BOARD_K8200 #1391

* K8200: new folder in example_configurations for Vellemann K8200 (3Drag
clone - should work with 3Drag http://reprap.org/wiki/3drag, too. Please
report)
* K8200/Configuration.h/Configuration_adv.h: updated manually with
parameters form genuine Vellemann Firmware "firmware_k8200_marlinv2"
based on the recent development branch

I tested the changes on my K8200 with 20x4-LCD and Arduino 1.0.5 for
Windows (SD library added to IDE manually) - everything works well