Register new model. Return 2valid object Parameters: modelName - name of the model, modelObject - model object
function (modelName, modelObject) {

    // check for name, object and if model already exists
    if (!modelName) return ('Name is not defined');
    if (!modelObject) return ('Model in ' + modelName + ' is not defined');
    if (this.registeredModels[modelName])
      return ('Model ' + modelName + ' is already registered');
    var o = Object.create(modelObject);
    this.registeredModels[modelName] = deepLook(o, this.types);
    return false;
  }