Correctly handle variable-length line terminators when parsing a response.
Correctly handle variable-length line terminators when parsing a response.

Previously, the hardcoded -3 assumed EOF+CR+LF line ending; receivers which
sent bare EOF chopped off 2 bytes of the parameters (if any) in the returned
message. e.g. sending listening-mode=query, which previously returned
  LMD (or ('listening-mode', ''))
now correctly returns
  LMD01 (or ('listening-mode', 'direct'))
on such a receiver (e.g. Integra DTR-30.2)

miracle2k/onkyo-eiscp,mrizvic/onkyo-eiscp