Review of std.net.isemail part 2

[Jacob Carlborg]

I've made a few minor changes:

* Renamed EmailStatusCode.Off -> None and On -> Any
* Added and clarified the documentation for EmailStatusCode.Any and None
* Updated the documentation

Github: https://github.com/jacob-carlborg/phobos/tree/isemail
Docs: http://dl.dropbox.com/u/18386187/isemail.html

-- 
/Jacob Carlborg