0.4.2

• Disable busy_limits_msgq on the Python port

  Under certain conditions busy_limits_msgq was putting the port into a busy state and never releasing it, even with {:queue_size, 0}.
  As a workaround before the bug is fixed in BEAM, remove this limit from Snex's Python ports.
  Compared to the pending-bytes busy_limits_port, it's not an important limit anyway.

Full Changelog: 0.4.1...0.4.2