New LV2 host implementation stack

I have released my new stack of libraries for implementing LV2 in hosts:

These libraries collectively replace SLV2, and have no dependencies except amongst themselves, and Glib (by Lilv and Sord, but this dependency will likely be removed in the near future). Serd and Sord replace Redland, making for a dramatically smaller implementation more appropriate for audio software and embedded applications.

Overall, Lilv is dramatically faster and leaner than SLV2, enough that the improvement should be quite noticeable from a user point of view (typically in a lag when the host first loads all LV2 data). Anyone using SLV2 is highly encouraged to migrate to Lilv.

These libraries are well tested, each (except Suil) with a test suite covering over 90% of the code, which runs without memory errors or leaks. They are new, however, so (as always) there may be problems; feedback is most welcome.