Conform to Codables

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Scope

So far OSCCore uses its own serialization technique. Swift 4 brings in Codables providing a standard way of doing it.

Transforming current implementation covers the following tasks.

• High level transformation: make compound types conform to Codable. Affected types are OSCMessage, OSCMessageArgument and OSCBundle.
• Low level transformation: provide own Encoder and Decoder - will be a quite hard task.
• Revisit tests: testing type to binary stream serialization and serialization details should be broken down to two parts (now details are verified in the same test pass).