Make the game engine use a start/end round and do healing if you don't make any mistakes.

game_engine.cpp

@@ -136,16 +136,28 @@ int GameEngine::determine_damage(string &type) {
   }
 }
 
+void GameEngine::start_round() {
+  hits_taken = 0;
+}
+
+void GameEngine::end_round() {
+  if(hits_taken == 0) {
+    heal();
+  }
+}
+
 bool GameEngine::hit(string &type) {
   int damage = determine_damage(type);
   hit_points -= damage;
+  ++hits_taken;
 
   // super dumb but I'll clean it up later
   return is_dead();
 }
 
-void GameEngine::heal(int amount) {
-  hit_points += amount;
+void GameEngine::heal() {
+  hit_points = hit_points * 1.10;
+  if(hit_points > 100) hit_points = 100;
 }
 
 bool GameEngine::is_dead() {