This is required when moving the buttons_init() function to the
lcd_init() function

Since the class "MainMenu" was used within a static variable the
initialization of the object (constructor call) was done before Arduino
library startup. It always caused a crash when using AVRStudio with
JTAG debugger (caused from calling the LCD initialization / the lot of
I/O work / the stack used during this calls). By moving the LCD_INIT
out of the constructor and using an explicit call inside of Arduino
setup() implementation immediately fixed all problems and the JTAG
debugger runs fine.

that pulls down the SDCARDDETECT pin and mimicking the pull and reinsert ofa a SD card

- redo disable Beeper if PIN is set to -1

Found a couple of unused variables, that I commented.
Tried to solve the program memory warning message, and failed.

Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1

Conflicts:
	Marlin/Marlin.pde
	Marlin/ultralcd.h