Enhancement: list methods if XMLRPC_GET_TEMPLATE not provided

I think showing the list of available methods is more useful that a static template. I patched my version to to include the approach taken here:

http://code.djangoproject.com/wiki/XML-RPC

Here's the patch if you want to consider adding it to the official version.

66a67
>
75c76,100
< return render_to_response(settings.XMLRPC_GET_TEMPLATE)
---
> try:
> return render_to_response(settings.XMLRPC_GET_TEMPLATE)
> except:
> response.write("<b>This is an XML-RPC Service.</b><br>")
> response.write("You need to invoke it using an XML-RPC Client!<br>")
> response.write("The following methods are available:<ul>")
> methods = xmlrpcdispatcher.system_listMethods()
>
> for method in methods:
> # right now, my version of SimpleXMLRPCDispatcher always
> # returns "signatures not supported"... :(
> # but, in an ideal world it will tell users what args are expected
> sig = xmlrpcdispatcher.system_methodSignature(method)
>
> # this just reads your docblock, so fill it in!
> help = xmlrpcdispatcher.system_methodHelp(method)
>
> response.write("<li><b>%s</b>: [%s] %s" % (method, sig, help))
>
> response.write("</ul>")
> response.write('<a href="http://www.djangoproject.com/"> <img src="http://media.djangoproject.com/img/badges/djangomade124x25_grey.gif" border="0" alt="Made with Django." title="Made with Django."></a>')
>
> response['Content-length'] = str(len(response.content))
> return response
>