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/boe.graphutil.h

@@ -4,7 +4,7 @@ void play_see_monster_str(unsigned short m);
 void draw_pcs(location center,short mode);
 void draw_outd_boats(location center);
 void draw_town_boat(location center) ;
-void draw_party_symbol(short mode,location center);
+void draw_party_symbol(location center);
 RECT get_monster_rect (pic_num_t type_wanted,short mode) ;
 RECT get_monster_template_rect (pic_num_t type_wanted,short mode,short which_part) ;
 RECT get_item_template_rect (short type_wanted);