We already have a LICENSE file that covers the Zig Standard Library. We
no longer need to remind everyone that the license is MIT in every single
file.
Previously this was introduced to clarify the situation for a fork of
Zig that made Zig's LICENSE file harder to find, and replaced it with
their own license that required annual payments to their company.
However that fork now appears to be dead. So there is no need to
reinforce the copyright notice in every single file.
Make the code easier for the optimizer to work with and introduce a fast
path for ASCII sequences.
Introduce a benchmark harness to start tracking the performance of ops
on utf8.
Thanks to the Windows Process Environment Block, it is possible to
obtain handles to the standard input, output, and error streams without
possibility of failure.
