Allow custom websocket implementations

[joreg]

By adding WS_PORT and WS_IP to the HostInfo as defined in the OSCQuery required attributes, we can implement the bi-directional websocket support outside of this library.

[momo-the-monster]

@joreg - thanks for submitting this PR. The OSCQuery spec is a little vague about how to specify that a server support Websockets or not. My best understanding is that a server that does not support them should not provide them as fields when returning a HOST_INFO request, but this implementation provides them by default now. What do you think about only including them if they are passed to the fluent constructor?

[joreg]

sounds good to me!