* ContractReference.cs, DiscoveryDocumentReference.cs: Delegate handling

	* ContractReference.cs, DiscoveryDocumentReference.cs: Delegate handling
	  of errors to the base class.
	* ContractSearchPattern.cs, DiscoveryDocumentLinksPattern.cs,
	  DiscoveryDocumentSearchPattern.cs, XmlSchemaSearchPattern.cs: Implemented.
	* DiscoveryClientProtocol.cs: Do not throw exceptions in ResolveAll method,
	  rather add them to the errors list.
	* DiscoveryReference.cs: Generate DiscoveryException where needed, so
	  DiscoveryClientProtocol can get the url for which an exception was thrown.
	* DiscoveryExceptionDictionary.cs: Implemented.

svn path=/trunk/mcs/; revision=23892