MeshBasedSelfConfigurators nullPointer

There is a null pointer exception computing a complex classifier with the meshbased selfconfigurator. StackTrace:

> > > > Walking along direction 1
> > > > Exception in thread "Thread-55" java.lang.NullPointerException
> > > > at de.uni_leipzig.simba.selfconfig.ComplexClassifier.clone(ComplexClassifier.java:31)
> > > > at de.uni_leipzig.simba.selfconfig.BooleanSelfConfigurator.learnClassifer(BooleanSelfConfigurator.java:230)

Reproduce: run Person11 - Person12 using the obvious property mapping computed by the stringmapper with scores 1.0
the start MeshBasedSelfConfiguration using defaults

Reproduce the failure by running Person11–Person12 with the stringmapper’s property mapping at score 1.0, then start MeshBasedSelfConfiguration with defaults. Inspect ComplexClassifier.java:31 and BooleanSelfConfigurator.java:230, where the stack trace identifies the null pointer. Done means the complex classifier computation completes without the exception.

Written by the indexing model from the issue text.