(web http): keys are always symbols

* module/web/http.scm (parse-media-type): Parse media types as symbols.
  (parse-key-value-list, parse-param-component, parse-param-list):
  Change kons to val-parser. Always parse keys as symbols, and always
  either cons, if there is a val, or just have the key, if there is no
  val.  Easier to explain and just as correct.
  (declare-param-list-header!, declare-key-value-list-header!): Adapt to
  key-list and param-list kons change.
  ("Cache-Control", "Pragma", "Transfer-Encoding", "Accept", "Expect")
  ("TE"): Likewise, adapt.
  ("Content-Type"): Param keys are symbols.

test-suite/tests/web-request.test

@@ -1,6 +1,6 @@
 ;;;; web-request.test --- HTTP requests       -*- mode: scheme; coding: utf-8; -*-
 ;;;;
-;;;; 	Copyright (C) 2010 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2010, 2011 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -61,12 +61,12 @@ Accept-Language: en-gb, en;q=0.9\r
        (request-headers r)
        '((host . ("localhost" . 8080))
          (user-agent . "Mozilla/5.0 (X11; U; Linux x86_64; en-us) AppleWebKit/531.2+ (KHTML, like Gecko) Safari/531.2+ Epiphany/2.30.2")
-         (accept . (("application/xml")
-                    ("application/xhtml+xml")
-                    ("text/html" (q . 900))
-                    ("text/plain" (q . 800))
-                    ("image/png")
-                    ("*/*" (q . 500))))
+         (accept . ((application/xml)
+                    (application/xhtml+xml)
+                    (text/html (q . 900))
+                    (text/plain (q . 800))
+                    (image/png)
+                    (*/* (q . 500))))
          (accept-encoding . ((1000 . "gzip")))
          (accept-language . ((1000 . "en-gb") (900 . "en"))))))