%xx escapes disallowed in host component

Hi Tim,

In <http://www.textuality.com/tag/uri-comp-4.html>:

[...]
Consider two URIs:

  * http://a/b 
  * http://a%2Fb 

Software applying RFC2396's rules would not find these equivalent, since
the %2F is being used explicitly to escape the special semantics in URIs
of the / character.
[...]

This example is invalid. The `host` component must not contain %xx
escapes, see section 3.2.2. of RFC 2396.

regards.