Lwt_unix: fix grammar/spelling in module overview
Lwt_unix.sleep: fix documentation grammar
Lwt_unix.yield: fix documentation grammar
Lwt_unix.auto_yield: fix documentation grammar
Lwt_unix.timeout: fix documentation grammar
Lwt_unix.on_signal: fix documentation grammar
Lwt_unix.accept_n: fix doc grammar/typos
Lwt_unix.readdir: fix wrong reference to Unix
Merge pull request #3 from agarwal/documentation

Documentation