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"

Fixes #1361

Improvement - G29 Option for Not Retracting Servo

Rambo FAN_PIN documentation and servo support

Move Sd library out into library

fix avrdude upload in makefile

Update GCodes.md

Removed remaining angle brackets which are not displayed properly in Github-flavored Markdown.

Independent PID parameters for each extruder

Reduce PROGMEM warnings

Update GCodes.md

Sort Gcodes numerically, other minor formatting changes

G29 E was not retracting the probe on the last probe point when used with ABL grid. Corrected.

* Adds config parameter `PID_PARAMS_PER_EXTRUDER` - allows single PID
parameters to be used where this would be preferable (e.g. dual
identical extruders)
* When disabled, will use `float Kp, Ki, Kd, Kc;` as before.
Preprocessor macros used to switch between.
* ultralcd.cpp defines extra menus for extra parameters only where
required
* M301 reports `e:xx` only if independent pid parameters enabled
* EEPROM structure still leaves space for 3 extruders worth, when undef
will save single parameter to all extruder positions, but only read the
first
* Switching off saves approx 330 B with no LCD enabled, 2634B with LCD
(RRD) enabled: this is significant.
* LCD modifications should be tested.