Don't redirect dynamic CSS from https to http

This can break things (d'uh).

Do this by introducing a new decorator, @ssl_optional. When this is
present, no SSL redirection will happen, regardless of whether the
access comes in over http or https.

This decorator overrides @ssl_required, but for redability's sake,
never use both at the same time.

pgweb/core/views.py

@@ -14,7 +14,7 @@ import os
 import re
 import urllib
 
-from pgweb.util.decorators import ssl_required, cache, nocache
+from pgweb.util.decorators import ssl_required, ssl_optional, cache, nocache
 from pgweb.util.contexts import NavContext
 from pgweb.util.helpers import simple_form, PgXmlHelper, HttpServerError
 from pgweb.util.moderation import get_all_pending_moderations
@@ -174,6 +174,7 @@ _dynamic_cssmap = {
 		     '../media/css/docs.css'],
 	}
 @cache(hours=6)
+@ssl_optional
 def dynamic_css(request, css):
 	if not _dynamic_cssmap.has_key(css):
 		raise Http404('CSS not found')