Serial Monitor: added "show timestamp" checkbox
Serial Monitor: added "show timestamp" checkbox

me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1,me-no-dev/Arduino-1