Looks good to me so far ;-)
First criticism I expect is for many to insist on a class-style vector library, which I personally think has no place as a low level, portable API. Everyone has a different idea of what the perfect vector lib should look like, and it tends to change significantly with respect to its application.
I think it would be useful, especially to newcomers who are unfamiliar with D's lib terrain, to have an officially supported "utils" library for these higher-level structures.
core // to the metal std // low-level but useful util // get the job done
