add more xml schema types, namely xs:normalizedString, xs:token, xs:Name, xs:NCName, ID and xs:language.

white_space='replace' and 'collapse' don't work yet.
a little bit more verbose exceptions for xml schema parser.
move s12{env,enc} prefixes to soap12{env,enc} to prevent them from being confused with user namespaces prefixes (s%d).
move spyne.const.xml_ns.const_prefmap generation to its own function.
fix simple model customization
add type name to types parsed from xml schema.
minor
Fail only when separate ComplexModelBase subclasses have conflicting (ns,name) pairs.

This relaxes previous constraint where no explicit type could end with RESPONSE_SUFFIX, RESULT_SUFFIX or TYPE_SUFFIX.
maquillage