Add 4th extruder

Add 4th extruder

Add 4th extruder

There’s no need to ask users to uncomment Max Endstop pins when they
have them. These will be set to -1 later if the endstop option is
disabled.

Hopefully this is helpful to organization and future expansion….

There’s no need to ask users to uncomment Max Endstop pins when they
have them. These will be set to -1 later if the endstop option is
disabled.

#1405 includes some changes to pins.h for a 4th extruder. This commit
applies those changes. It also deals with a possible problem with
SENSITIVE_PINS.

Hopefully this is helpful to organization and future expansion….

Add PID_dT in temeprature.cpp

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

Replace instances of the number 13 with FILENAME_LENGTH where
appropriate.

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

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

Replace instances of the number 13 with FILENAME_LENGTH where
appropriate.

Formatting for code-folding plus minor style changes to less active
code.

Done

This define is not used.

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

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

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