Some cleanup and refactoring.

Superfluous methods removed.

CascadeHiddenNeuronCorrelationProblem and CascadeOutputLayerTrainingProblem
now must be initialised by CascadeCorrelationProblem rather than doing it
automatically.

CascadeHiddenNeuronCorrelationProblem and CascadeOutputLayerTrainingproblem
now calculates domains everytime they are initialised rather than everytime
getDomain is called.

CascadeCorrelationAlgorithm now only tries to set up
CascadeOutputLayerTrainingProblem once.

Some more unit testing code added to CascadeCorrelationAlgorithmTest.