Adapt to latest Tox API changes

* tox_bootstrap_from_address() no longer takes port in network byte
  order and no longer takes a ipv6enabled parameter.
  See projecttox-core commit 7557b92fc9699e0c762e627f97b4d997506ddedf

* tox_new() now takes a Tox_Options struct as argument
  See projecttox-core commit ef78169842514d6f8507caebb7f791b9227812bf