*) core/mod_http: use REQUEST meta buckets and a new HTTP/1.x specific
     input filter to separate the handling for HTTP requests from the
     handling of HTTP/1.x request parsing and checks.
     A new HTTP1_REQUEST_IN filter installs itself on http/1.1 connections
     before a request is being read. It generates either a REQUEST meta
     bucket on success or an ERROR bucket with the proposed response status.
     The core connection processing, relying on ap_read_request(), now expects
     a REQUEST or ERROR bucket from the input filters and is agnostic to
     specific HTTP versions and how they bring requests into the server.
     [Stefan Eissing]