Allow the session authenticate signal to be handled asynchronously, by

Allow the session authenticate signal to be handled asynchronously, by

	* libsoup/soup-auth-manager.c (authorize_handler, etc): Allow the
	session authenticate signal to be handled asynchronously, by
	pausing the message and then authenticating the auth later.
	(auth_type_compare_func): make this work. oops.
	(extract_challenge): plug leak

	* libsoup/soup-auth-manager-ntlm.c: Make this work async too.

	* libsoup/soup-headers.c (soup_header_parse_list):
	(soup_header_parse_param_list): plug leaks

	* tests/auth-test.c (do_async_auth_test): test async auth

	* docs/reference/client-howto.xml (Handling Authentication):
	mention async auth

svn path=/trunk/; revision=1045