Error that type already exists during typesystem load

[UWinch]

Describe the bug
I have a typesystem that contains a type without namespace e.g. TestType and one with namespace e.g. my.cool.TestType. When I try to load the typesystem from xml, I sometimes get a ValueError: Type with name [TestType] already exists! . I think this happens when the type with the longer name has already been added to the typesystem during creation and the shorter one is about to be added. In

dkpro-cassis/cassis/typesystem.py

Line 883 in 2ca9bbe

if self.contains_type(name) and not is_predefined(name):

contains_type evaluates to True because the contains method checks shortname retrieval of the type.

To Reproduce
Steps to reproduce the behavior:

1. Have a typesystem containing the type my.cool.TestType
2. Try creating the type TestType

Please complete the following information:

• Version: 0.10.0
• OS: Linux