Marlin with ATmega1284p sanguino support under Arduino 023

This change allows fan outputs to automatically turn on/off when the
associated nozzle temperature of an extruder is above/below a threshold
temperature.
Multiple extruders can be assigned to the same pin in which case the fan
will turn on when any selected extruder is above the threshold.
It also makes the M42 command compatible with the M106/M107 command.
The majority of the logic in this change will be evaluated by the
compiler at build time (i.e, low code space requirements).

Refactor configuration to try to make items clearer (what defines a
panel vs what is user changeable).

Added the optiboot bootloader, uses only 512kB of FLASH
Includes .hex file is for 20MHz µC Clock and serial speed of 57k6

This is the actual Sanguino release for Arduino 023.
It has full ATmega1284p support.

Reference:
https://code.google.com/p/sanguino/downloads/detail?name=Sanguino-0023r4.zip&can=2&q=

ATmega644P 16MHz, ATmega1284p 8, 16, 20MHz

Also fix compile time check in Marlin.pde

This includes refactoring the buttons code to remove a large amount of
non-pin dependent duplication from pins.h.

Hotend offset handling for multi-extruder machines

Removed incorrect LiquidCrystal_I2C Library

Conflicts:
	Marlin/language.h
	Marlin/thermistortables.h

Marlin v1, alignment of the Italian language

Update Marlin/language.h

Update Polish language 	#define MSG_RESUMING "Wznawiam drukowanie"

Add SD-Card change and SD-Card init. for electronics equipped with LCD Display

Update Marlin/ultralcd_implementation_hitachi_HD44780.h

Fix to a bug that I just introduced - sorry. Forgot about offset of string length.

Add SD-Card change and SD-Card init. for reprap electronics without
SD-Chard change detect pin.

Update Marlin/ultralcd_implementation_hitachi_HD44780.h

Use all available characters in narrow LCDs < 20 characters.

Fix to a minor bug with hardcoded LCD_WIDTH that draws edited values outside of the 16 characters width LCDs.

The extruder offset can be specified in the configuration
file or adjusted on the fly using the "M218 T# X# Y#" command.
The EEPROM support is not yet merged in.
The "T#" command can take option "F#" that specifies the feedrate
at which the printing head should be re-positioned. If not
specified the re-positioning move is not preformed immediately,
but the coordinates are adjusted for the printer to properly
position the head when the next movement happens.

Also skip .files and _files with long filenames. I think its better than before. If somebody dislikes it, or wants additional configuration, it can be done in a future step. Thanks, Marius, and nice to have you helping!

Chenged LED_PIN for Melzi boards, added comment about broken versions of...

compile fix: quickStop() needs stepper.h

This reverts commit 01541ee64c.

[default off for now]
syntax: M600  X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]

if enabled, after a M600, the printer will retract by E, lift by Z, move to XY, retract even more filament.
Oh, and it will display "remove filament" and beep like crazy.

You are then supposed to insert a new filament (other color, e.g.) and click the display to continue.
After having the nozzle cleaned manually, aided by the disabled e-steppers.
After clicking, the printer will then go back the whole shebang, and continue printing with a fancy new color.

Marlin v1, italian MSG_RESUMING and RepRapPro thermistor tables.