A few more scenario read tests

- Introduce enum for scenario content rating

src/classes/estreams.cpp

@@ -631,3 +631,18 @@ std::istream& operator>> (std::istream& in, eAttitude& att) {
 		in.setstate(std::ios::failbit);
 	return in;
 }
+
+// MARK: eContentRating
+
+cEnumLookup rating_strs = {"G", "PG", "R", "NC-17"};
+
+std::ostream& operator<< (std::ostream& out, eContentRating rating) {
+	writeEnum(out, rating, rating_strs, "docile");
+	return out;
+}
+
+std::istream& operator>> (std::istream& in, eContentRating& rating) {
+	if(!readEnum(in, rating, rating_strs, eContentRating::G))
+		in.setstate(std::ios::failbit);
+	return in;
+}

src/classes/scenario.cpp

@@ -69,7 +69,7 @@ cScenario::cScenario() {
 	where_start.x = 24;
 	where_start.y = 24;
 	out_start = where_start;
-	rating = 0;
+	rating = eContentRating::G;
 	difficulty = 0;
 	intro_pic = intro_mess_pic = 0;
 	adjust_diff = true;
@@ -133,7 +133,7 @@ void cScenario::append(legacy::scenario_data_type& old){
 		special_items[i].flags = old.special_items[i];
 		special_items[i].special = old.special_item_special[i];
 	}
-	rating = old.rating;
+	rating = eContentRating(old.rating);
 	// TODO: Is this used anywhere?
 	uses_custom_graphics = old.uses_custom_graphics;
 	for(i = 0; i < 30; i++) {

src/classes/scenario.hpp

@@ -72,7 +72,8 @@ public:
 	std::vector<cSpecItem> special_items;
 	std::vector<cQuest> quests;
 	std::vector<cShop> shops;
-	short rating,uses_custom_graphics;
+	short uses_custom_graphics;
+	eContentRating rating;
 	std::vector<ePicType> custom_graphics;
 	std::vector<cMonster> scen_monsters;
 	std::array<cVehicle,30> boats;
@@ -122,4 +123,7 @@ public:
 	~cScenario();
 };
 
+std::istream& operator>> (std::istream& in, eContentRating& rating);
+std::ostream& operator<< (std::ostream& out, eContentRating rating);
+
 #endif

src/classes/simpletypes.hpp

@@ -38,6 +38,8 @@ inline eDirection& operator++ (eDirection& me, int) {
 	else return me = (eDirection)(1 + (int)me);
 }
 
+enum eContentRating {G, PG, R, NC17};
+
 enum class eQuestStatus {AVAILABLE, STARTED, COMPLETED, FAILED};
 
 enum class eMainStatus {