added docs

lib overview
neuron link

added attributes and operations
review of NeuronLink methods done
review of Layer methods (nearly) done

added LayerData and NetworkData
removed networkData & layerData

changed types of connections, added some operations
added some attributes and operations
added matrixLayer and neuronLayer
matrixLayer updated
neuron- and neruonlinkmatrix changes
Merge pull request #2 from emmanuel099/doc

Doc