Add support for base types

Add main schema to schema array so that it would be possible to search base types and nillable members also in main wsdl file(s)

Add support for custom XML Schema prefix
Remove dependency on type order for inheritance.

- Update test case to check for type order independency.
- Move test incomplete marker and check for abstract case to the bottom
of test case to make test fail if random type order is not supported.
- Check for inheritance after all classes have been loaded.
- Load base classes where needed to avoid dependency on order in Service class.
Add abstract test case.

This tests handling of abstract and extended classes.

The test is currently incomplete as the code does not handle this properly.
Refactor Validator.

Move all name changes caused by validation to Validator class. This means we no longer need the ValidationException class.

Simplify Validator class methods. There is no need to separate class/operation/etc. validation from name validation.

Added methods to validate constant and attribute names.
Fix location of type nodes if no prefix is used.
Code style fixes
Merge branch 'base-type-support'