#57 Improve type system handling of boundary matchers

[Peter Klügl]

Improve type system handling of boundary matchers, like LP2. Currently, the user needs to add the additional types to the preprocess script. The (boundary) types should be created by the TextRuler framework and automatically added to the learnt script. This means, that the types system the leanrer is based on needs to be extended in the background by the framework.