Modified the DAV widgets to handle the rendering and parsing

of all webdav properties to and from Python xml.dom elements.

Clarified some of the fields in the DAV schema in order to
take advantage of the new widgets. Also reworked a big chunk
of PROPFIND to take advantage tof the new widgets.

Also added a basic implementation of the COPY, LOCK and
UNLOCK methods.

Make the ILockStorage utility in zope.app.locking addable
through the site management interface.

methodnotallowed.txt

@@ -0,0 +1,31 @@
+Method Not Allowed errors
+=========================
+
+If we get a request with a method that does not have a corresponding
+view,  HTTP 405 Method Not Allowed response is returned:
+
+  >>> print http(r"""
+  ... FROG / HTTP/1.1
+  ... """)
+  HTTP/1.1 405 Method Not Allowed
+  Allow: COPY, DELETE, MKCOL, OPTIONS, PROPFIND, PROPPATCH, PUT
+  Content-Length: 18
+  <BLANKLINE>
+  Method Not Allowed
+
+  >>> print http(r"""
+  ... DELETE / HTTP/1.1
+  ... Authorization: Basic mgr:mgrpw
+  ... """)
+  HTTP/1.1 405 Method Not Allowed
+  ...
+
+The request below should return 405, but instead crashes with a TypeError,
+when the view tries to adapt context to IWriteFile.
+
+#   >>> print http(r"""
+#   ... PUT / HTTP/1.1
+#   ... Authorization: Basic mgr:mgrpw
+#   ... """, handle_errors=False)
+#   HTTP/1.1 405 Method Not Allowed
+#   ...