Nuke as many warnings as possible, and several globals as well

- Warnings completely suppressed for the included TinyXML and gzstream libraries
- Parentheses warnings are now errors, since there were several that looked like bugs
- Ditto for dangling else warnings

Some of these warnings were actually bugs:
- Town wandering monsters would have never spawned, because the code to do so was accidentally nested within a check for overall_mode == MODE_OUTDOORS
---> boe.monster.cpp, lines 105-137
- Monster's behaviour with respect to elemental fields did not correctly depend on their immunities (this is the same precedence issue Sylae messed up fixing in the Windows code)
---> boe.monsters.cpp, lines 345-359
- Display of damage blocked by armour appeared to be incorrect (needs verification)
---> boe.newgraph.cpp, line 1079
- Three-choice dialogs probably weren't dealing with unusual button types correctly, though that's a minor point since they aren't expected to use such buttons

osx/pcedit/pc.action.h

@@ -2,7 +2,7 @@
 #include <SFML/Window/Event.hpp>
 #include "dialog.h"
 
-bool handle_action(sf::Event event,short mode);
+bool handle_action(sf::Event event);
 void flash_rect(RECT to_flash);
 void edit_gold_or_food(short which_to_edit);
 void display_pc(short pc_num,short mode,cDialog* parent);