Add new Claxon-vs-libflac benchmark results
Add new Claxon-vs-libflac benchmark results

After the LLVM upgrade in Rust 1.25.0, rustc started generating better
code. This brings Claxon closer to libflac performance, without any
effort on my part! I re-ran the tools/benchmark_against_libflac.sh
script with a Rust 1.26.0 toolchain, and now Claxon is within 10% of
libflac performance, yay!

Somebody should try recompiling libflac with a recent Clang then though,
it might undo the advantage again. Although Claxon probably benefits
more from optimizations than libflac does, because libflac is full of
manually vectorized code and low-level optimizations. Claxon's code is
far more high-level (still optimized to ensure that the compiler can
generate fast code from the high-level code though).

ruuda/claxon,ruuda/claxon,ruuda/claxon