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.

Removed incorrect LiquidCrystal_I2C Library

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.

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 01541ee6.

[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.

Panelolu pin assignment for sanguinololu