Use secure defaults for static middleware.

These changes affect the security defaults and will definitely provide better behaviour for the existing users.
Issue #64 - Implementating noDots by default.
Issue #63 - Implementating isNotAbsolute by default tightens up the security to a normal standard.

Previous request on `localhost:3000//etc/passwd` would print out the contents of `/etc/passwd`. With the added security, the request will now return 404.
Merge pull request #81 from nhibberd/master

Use secure defaults for static middleware.