def <<(item)
    if(item.kind_of? Zyps::GameObject)
      self.add_object(item)
    elsif(item.kind_of? Zyps::EnvironmentalFactor)
      self.add_environmental_factor(item)
    else
      raise "Invalid item: #{item.class}" 
    end
    self
  end
def <<(item)
    if(item.kind_of? Zyps::GameObject)
      self.add_object(item)
    elsif(item.kind_of? Zyps::EnvironmentalFactor)
      self.add_environmental_factor(item)
    else
      raise "Invalid item: #{item.class}" 
    end
    self
  end
Overloads the << operator to put the new item into the correct list.
This allows one to simply call env << <valid_object> instead of
having to choose a specific list, such as objects or environmental factors.