RFC 9110 fix part deux

Previous release did not fix all problems with, for instance, underscores in HTTP field names. This release properly fixes such cases and also makes the HTTP server 14% faster in user space.

A new benchmarking project has been added for reliably benchmarking the entire user space portion of the server by overriding epoll syscalls with traffic producing alternatives. This is a similar approach to how we currently fuzz the user space.