Make path and open tiles more legible

Change markers chars to be more legible

main.cc

@@ -97,10 +97,10 @@ class World
 							cout << "T";
 							break;
 						case DISCOVERED:
-							cout << "+";
+							cout << ":";
 							break;
 						case TRACE:
-							cout << "*";
+							cout << "+";
 							break;
 					}
 				}