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/dialogxml/control.h

@@ -75,7 +75,7 @@ public:
 	cKey getAttachedKey();
 	virtual void attachClickHandler(click_callback_t f) throw(xHandlerNotSupported) = 0;
 	virtual void attachFocusHandler(focus_callback_t f) throw(xHandlerNotSupported) = 0;
-	virtual bool triggerClickHandler(cDialog& me, std::string id, eKeyMod mods, location where);
+	virtual bool triggerClickHandler(cDialog& me, std::string id, eKeyMod mods);
 	virtual bool triggerFocusHandler(cDialog& me, std::string id, bool losingFocus);
 	//virtual void setPict(short pict, short type) = 0;
 	virtual void show(); // cd_activate_item true