contrib: Update libsamplerate.

contrib: Update libsamplerate.

I've asked upstream a couple times to push at least one tag, but it seems the maintainer is busy with other projects. Imagining a world where libsamplerate 0.1.9 was tagged, this is libsamplerate 0.1.9-35-g02ebb9f.

Numerous improvements include upstream moving from bzr to git, modernizing and cleaning up the autotools-based build system, fixing issues involving GCC 7, and *nine* years of improvements to the code base.

libsamplerate is now under a 2-clause BSD license.