* MapCodeGenerator.cs: Changed some methods to make them easier to reuse.

	* MapCodeGenerator.cs: Changed some methods to make them easier to reuse.
	* TypeTranslator.cs: NMTOKENS, ENTITIES and IDREFS must be mapped to
	  string, not string[].
	* XmlCodeExporter.cs: AddMappingMetadata(): improved attribute generation
	  for array parameters. In general, improved generation of schema Form
	  property.
	* XmlMemberMapping.cs: Added Form property.
	* XmlReflectionImporter.cs: Types that inherit from other types cannot be
	  simple types. Added a check for this.
	* XmlSchemaExporter.cs: several fixes: better generation of IsMixed and
	  Form. The key used to determine if a map has been already generated must
	  include the XmlType, since there can be two xml types with the same CLR
	  type and namespace (for example, they may differ in the Form property).
	* XmlSchemaImporter.cs: When getting the TypeData for a schema element,
	  also return the corresponding map. There can be two maps that have the
	  same TypeData, so given a TypeData is not always possible to get the
	  correct corresponding map (for example two arrays that only differ in the
	  Form of the item).
	* XmlTypeMapping.cs: Added method to set if a map can represent a simple
	  type or not.

svn path=/trunk/mcs/; revision=22968