Benchmark compile times

[Ralith]

Given rust's reputation in this area, it would be useful to publish how long both clean (fresh checkout) and incremental (touch every .rs file but don't change anything) builds of the suite take. This could be accomplished by feature-guarding each lib, and for maximum clarity in the results, omitting tests that pull in heavy deps like serde which might otherwise be avoided.

[kettle11]

I strongly agree! It'd be great if compile times were included in most Rust benchmarks. It's an important factor to weigh when evaluating a Rust library.