Multi-host support

Marlin/Configuration.h

Marlin/src/HAL/HAL_AVR/HAL_AVR.cpp

Marlin/src/HAL/HAL_AVR/HAL_AVR.h

Marlin/src/HAL/HAL_AVR/HAL_pinsDebug_AVR.h

Marlin/src/HAL/HAL_AVR/pinsDebug_AVR_8_bit.h

Marlin/src/HAL/HAL_DUE/EepromEmulation_Due.cpp

Marlin/src/HAL/HAL_DUE/HAL_Due.h

Marlin/src/HAL/HAL_LPC1768/HAL.cpp

Marlin/src/HAL/HAL_LPC1768/HAL.h

Marlin/src/HAL/HAL_LPC1768/arduino.cpp

Marlin/src/HAL/HAL_LPC1768/main.cpp

Marlin/src/HAL/HAL_LPC1768/serial.h

Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.h

Marlin/src/HAL/HAL_TEENSY35_36/HAL_Teensy.h

Marlin/src/Marlin.cpp

Marlin/src/core/serial.cpp

Marlin/src/core/serial.h

Marlin/src/feature/bedlevel/abl/abl.cpp

Marlin/src/feature/bedlevel/ubl/ubl.cpp

Marlin/src/feature/bedlevel/ubl/ubl.h