merged matrix activationfunctions and normal activationfunctions

(overloaded functions in activationfunction.h)

replaced "createnetwork(layersizes)" with "addInputLayer(...)",
"addHiddenLayer(...)", "addOutputLayer(...)"

added "addLayer(...)" to the networkfactory to add layers with different actfunctions

fixed bug in neuronmatrix: setDesiredOutputValues():
error was squared two times