GcodeParser: add getBuffer() function. Will be used in SD card code to detect EOF.
GcodeParser: add getBuffer() function.
Will be used in SD card code to detect EOF.

johnkingsley/aprinter,johnkingsley/aprinter,ambrop72/aprinter,johnkingsley/aprinter,fixator/aprinter,johnkingsley/aprinter,ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,ambrop72/aprinter,fixator/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,fixator/aprinter,ambrop72/aprinter,fixator/aprinter,ambrop72/aprinter,fixator/aprinter,fixator/aprinter