Use Oscpack instead of liblo (and make OSC work on macOS)

[aalex]

To ease building MapMap on Windows and macOS, we will transition to Oscpack.

Related issues:

• OSC works only after opening the console #350
• OSC is not supported on Windows #284
• OSC is not supported on MacOS #283
• OSC server sometimes doesn't work #34
• OSC Monitor  #96

[aalex]

See also #353

[aalex]

Here is a working prototype: https://github.com/mapmapteam/proto-qtoscpack