Area::get_building_datum() doesn't return NULL on fail; instead return Building_data[BUILD_NULL] for safety.
Add hovels and manor back into the game.
Area data for hovels and manor.  Don't capitalize "houses" for consistency.
Building_datum has a constuctor/destructor.  Track whether the name is plural (e.g. "houses").  Housing is now a vector (if we house different classes, e.g. keep).  Track number of soldiers supported (e.g. barracks).
Can set buildings as plural.  Rename "hovel" -> "hovels" and "house" -> "houses."  Barracks support 50 soldiers.  Constructor/destructor for Building_datum.  Update Building_datum::get_short_description() to support vector of housing.
lookup_citizen_name() takes a bool; if true, returns pluralized name (defaults to false).  citizen_food_consumption() returns the amount of food a citizen of that class eats every day.
New City functions; get_total_housing(), get_military_count(), get_military_supported(), get_food_consumption(), get_food_production().  get_total_population(), get_total_housing() and get_food_consumption() can take a Citizen_type parameter; if so, returns values for just that Citizen_type.  If ommitted (or CIT_NULL is passed), return summed values for all Citizen_types.  City stores a vector of military units stationed there.
Rename MENU_BUILD to MENU_BUILDINGS for clarity.  Better commenting / whitespace.  New function, Interface::display_area_stats(), puts city stats relevent to the specified Area_type into text_options.
Minor improvements.  Interface::display_area_stats() is called after we choose an area to build via pick_area(); it puts City stats relevent to the selected area into text_options.
Make Map::get_resource_info(), Map::get_terrain_datum(), Map::get_glyph() and Map::get_info() accept a Point OR a pair of ints.  The Point-based function just calls the int-based function.
Rudimentary struct for military units.