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.

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

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

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

* Boards.h: updated comment for board 3Drag - K8200 removed
* Boards.h: added `BOARD_K8200` with ID 78

* language.h.: machine name and firmware URL for new board

* pins.h: added `K8200` to any `#if` with `3Drag` and corresponding
comments

Show Custom M Code when entering M503

Update Boards.h for Vellemann K8200 - comment only

Remove hardcoded programmer option (-cwiring).

This reverts commit 935ee968a7.

Still not fine tuned but working.

When a melzi board and a full gfx are both selected, the build fails
blaming for some missing defines.

This is a fix for the issue: now my configuration works.

## Update Boards.h for Vellemann K8200 - comment only

* Boards.h: updated comment for board 3Drag - K8200 uses same board

This reverts commit 5333590ac2.

* K8200: new folder in example_configurations for Vellemann K8200 (3Drag
clone - should work with 3Drag too, please report)

* K8200/language.h: updated machine name and URL for K8200

* K8200/Configuration.h/Configuration_adv.h: updated manually with
parameters
form genuine Vellemann Firmware "firmware_k8200_marlinv2" based on the
recent development branch

* K8200/files by Vellemann: added folder with original files from
Vellemann homepage, since there is no GitHub fork you could link to by
them

I tested the changes on my K8200 with 20x4-LCD and Arduino 1.0.5 for
Windows - everything works well

Change default value of AVRDUDE_PROGRAMMER to 'wiring'.

Revert "Reduce PROGMEM warnings"

Update printrboard pin assignments

Backported from Printrbot branch, allows the fan to work correctly.

Revert "Move Sd library out into library"