Some fixes to lo-byte parser
Some fixes to lo-byte parser

- The lo-byte parser would incorrectly call buf.copy() with an offset at
  the end of the target buffer and a length of 0. Though this is
  theoretically a no-op, Buffer.copy() is doing bounds-checking on the
  source before taking the length into account.
- Clear bufs[] and bufBytes when consuming partial buffer.

takano32/node-websocket-client,pgriess/node-websocket-client