XSD types always have lowercase package names

In 9.0, the generation of XSD types always has lowercase packages names in Gosu.

For example, suppose an XSD file is at the path gsrc/example/MyTest.xsd and contains an element called Address. In 8.0, the type was example.MyTest.Address. In 9.0, the type is example.mytest.Address. If you get Gosu compilation errors due to this change, fix the capitalization of the package names.