Add a simple threaded hello world example.
Merge pull request #105 from reem/hello-world

Add a simple threaded hello world example.
Basic Cookie and Set-Cookie (only parsing) headers implementation.
Add cookie-rs and use `cookie::Cookie` in `Cookie` header.
Build SetCookie from CookieJar
Add cookie_rs as default feature and implement conditional compilation.
adjustments to Cookie and SetCookie