Move model specific class members from layout.h to the 911 and Neuro specific sub-classes.

[jardiamj]

The file: /Simulator/Layouts/Layout.h contains 911 and Neuron specific class members. The 911 specific members are only used for initialization so these can be moved to layout911.h:

   BGSIZE numCallerVertices_
   ...

   vector<int> callerVertexList_;    ///< Caller vertex list.

   vector<int> psapVertexList_;    ///< PSAP vertex list.
   
   vector<int> responderVertexList_;    ///< Responder vertex list.

The Neuron specific class members are being used in the implementation of printParameters() for printing to the logging file. It seems to me that, since these parameters are model specific, the printParameters() method could be an abstract method to be implemented by the model specific sub-classes, the same way we are doing it with loadParameters().

layout.h Neuro specific class members:

   vector<int> probedNeuronList_;
   ...
   BGSIZE numEndogenouslyActiveNeurons_;
   ...
   vector<int> endogenouslyActiveNeuronList_;    ///< Endogenously active neurons list.

   vector<int> inhibitoryNeuronLayout_;    ///< Inhibitory neurons list.

[stiber]

I think that the probedNeuronList_ could be renamed probedVertexList_ and kept at the top level. Actually, I believe that this is going to be/is being moved to the Recorder classes, right, @kimjamesuw?

[stiber]

See also #843