Fix mod_rewrite's abs_URI handling.

- uris were partially not correctly escaped (in particular:
  ldap, news, mailto)
- not all uri schemes contain an authority component (//)
- add nntp:// scheme
- don't add a query string (and drop r->args) if it's not
  http or mailto scheme
- be more efficient (think so)

Reviewed by: Justin Erenkrantz, Brian Pane


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@99915 13f79535-47bb-0310-9956-ffa450edef68