Get unit test framework running (+riders)

Changes in this pull request:

* Add [Catch][] as `playd`'s unit test runner.  Currently, there are no unit tests (bar a stub one to ensure that the test runner is working).  Get writing!
* Do a bit of spring cleaning on the GNU makefile, factoring out the GitHub Pages updating logic to a separate script, as well as adding a `make test` rule for running the unit tests.
* Add [`BSDmakefile`][], an experimental [BSD make][] Makefile that can be used when building on *BSD.  This is probably going to be controversial, but see the [commit message][] for a (somewhat weak) rationale.  The GNU Makefile will remain the primary build mechanism across all POSIX platforms; this is mainly for convenience when building on *BSD and building ports.
* Add the PortAudio C++ headers to the `contrib` bundle.
* Add a call to `ldconfig` into [`make_libuv.sh`][] to fix running the test suite via [Travis][].

In addition, some spurious binary files added by accident by a previous branch have been removed.  My bad.

[Catch]: http://www.catch-lib.net
[`make_libuv.sh`]: https://github.com/UniversityRadioYork/ury-playd/blob/651bb72f304f02d37385226623d62a277a21d56f/make_libuv.sh#L18-L21
[Travis]: https://travis-ci.org/UniversityRadioYork/ury-playd
[BSD make]: https://www.freebsd.org/doc/en/books/developers-handbook/tools-make.html
[`BSDmakefile`]: https://github.com/UniversityRadioYork/ury-playd/blob/816c9b395682a2ce8dae60a2abaa13d72aea5638/BSDmakefile
[commit message]: https://github.com/UniversityRadioYork/ury-playd/commit/6ddcb89727fba062dcf179c44e666a44b802fc1f