add suppor with RAMPS-FD  base on boco firmware

add suppor with RAMPS-FD  base on boco firmware
for hardware design reason , add new function to invert output logic
level.
Original code is writen by bobc (https://github.com/bobc/Repetier-Firmware) ,I just merge  the bobc's  code with the latest version 0.91 and pull the request ,This code is  working good  with ramps-fd with arduino due .I have tested with delta.