TODO: modify other races constructors

did some reworking

src/potion.h

@@ -4,6 +4,7 @@
 #include <vector>
 #include "constants.h"
 #include "fraction.h"
+#include "display.h"
 
 // IMPORTANT: pop all potions of duration == 0, and when entering a
 //  new level, pop all potions of duration == -1
@@ -31,6 +32,8 @@ public:
         int get_duration() const;
         position get_pos() const;
         void set_pos(const position &npos);
+
+        virtual void print(display *out, bool color = false);
 };
 
 typedef std::vector<potion *> potion_list;