Minor dialogue and UI bug fixing

src/Character.h

@@ -117,8 +117,19 @@ public:
 
     std::string npcId;
     std::string npcName;
-    float hp = 200.f;
     float initialHp = 200.f;
+protected:
+    float hp = 200.f;
+public:
+
+    float getHp() const {
+        return hp;
+    }
+
+    void setHp(float newHp) {
+        hp = newHp;
+        if (onHpChanged) onHpChanged(hp, initialHp);
+    }
 
     // The position the NPC should return to if pushed too far away.
     // Initialised to the spawn position; updated whenever a script walk command is issued.