Starting to close the loop

* Added ISurroundings, which is something and organism can use for information regarding the immediate surroundings

* Added age and basic metabolism for organisms.
* Customized EnvironmentSpace and EnvPartition.
** EnvironmentSpace will be the primary world model, splitting space until EnvPartition instance
** Each EnvInstance will implement ISurroundings and will be made available to each organism upon entering it.  For now there is a Space<IFood> there and all organisms in the partition are registered with it.
* Added population monitoring thread  to SimScreen
* Added FoodBitterAbility which queries for local food and bites it if in range
* Added QueryClosestFoodAbility which returns the local vector to food