Don't share the same temporary scenario directory between all programs

(Also fixes loading of unpacked scenarios)

src/pcedit/pc.main.cpp

@@ -33,6 +33,7 @@ rectangle traits_rect; //Holds the string "Traits:"
 rectangle pc_traits_rect[16]; //Holds pc traits
 rectangle pc_race_rect; //Holds current pc's race
 rectangle edit_rect[5][2]; //Buttons that bring up pc edit dialog boxs
+std::string scenario_temp_dir_name = "pc_scenario";
 
 short current_active_pc = 0;