literate stdlib docs

repo: http://ratfactor.com/repos/zstd-browse2/
docs: http://ratfactor.com/zig/stdlib-browseable2/std.zig.html

@ratfactor make the zig stdlib docs into a docco-style annotated website, which is really nice because the stdlib is pretty much undocumented so when you write zig you need to refer to it frequently.