added result screens

fixed bug about picking up two boosts crashing the game

src/output/curses_output.cc

@@ -9,8 +9,10 @@ void curses_output::render() {
         curse->show();
 }
 
+std::string BLANK(DISPLAY_BUFFER_SIZE, ' ');
+
 void curses_output::clear() {
-        curse->clear();
+        print_str({0, 0}, BLANK, A_NORMAL);
 }
 
 void curses_output::print_char(const position &pos, const char ch,