Refactor transport-level code in preparation for TCP support

[daveyarwood]

Background

See my comment here: https://github.com/hoijui/JavaOSC/issues/12#issuecomment-559085565

To summarize, the current implementation of JavaOSC is UDP only, and there is a lot of transport-level code (all UDP-specific) in OSCPortIn and OSCPortOut.

I plan to implement TCP support soon, and I want for users to be able to continue to use the same public API, with only the small additional step of setting the network protocol to TCP, something like this:

new OSCPortInBuilder().setPort(12345).setNetworkProtocol(TCP).build();

As a first step towards that, this PR refactors / reorganizes the parts of the codebase that have to do with transport. The next step will be to simply add a TCPTransport class and OSCPort{In,Out}Builder methods to allow the user to specify the network protocol.

Summary of changes

• BREAKING Move higher-level transport.udp.OSCPort* classes up a level to transport.OSCPort*.

  • Most of the code in these classes has nothing to do with UDP transport specifically, and is more about the transport of OSC messages at a higher level.

• Added a Transport interface that captures the low level implementation details.

• Moved the current UDP transport implementation into UDPTransport, which implements Transport.

• Adjusted the toString implementations of OSCPort et al to include information about the Transport.

• OSCParseExceptions now include the data we attempted to parse

  • see https://github.com/hoijui/JavaOSC/commit/e2b9daffd15d5b78f105628d3e7095d0d923927d
  • Allows the higher level OSCPortIn class to handle the data without needing to reach down into the transport implementation.

Feedback welcome! :slightly_smiling_face:

[daveyarwood]

Closing this in favor of #52, which includes these commits and many more!