Add support for i2c slave address

Fix serial output for MBL, M303

Update language_de.h with MSG_MOVE_E1 - E4

MSG_MOVE_E1 was missing
MSG_MOVE_E2 was missing
MSG_MOVE_E3 was missing
MSG_MOVE_E4 was missing

I assigned "0" to "MSG_MOVE_E1", "1" to "MSG_MOVE_E2" and so on, as this is what i assume to be the standard naming for the first (E0) and second (E1) extruder. This would have to be changed inthe other languages too :(

Include days in Graphical LCD print timer

Throw MINTEMP BED error only if heating

Show up to 99:59 in digital time

Patch command order in delta calibration menu

Make DELTA_CALIBRATION_MENU more universal

MISO is an input

Always disable SLOWDOWN for DELTA/SCARA

Fix Z_DUAL_ENDSTOPS with Z MIN Homing

Explain that Z_PROBE_*_HEIGHT options are nozzle-relative

Within Marlin, maintain most feed rates in mm/s