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/scrollbar.cpp

@@ -53,11 +53,11 @@ void cScrollbar::attachClickHandler(click_callback_t f) throw(xHandlerNotSupport
 	onClick = f;
 }
 
-void cScrollbar::attachFocusHandler(focus_callback_t f) throw(xHandlerNotSupported) {
+void cScrollbar::attachFocusHandler(focus_callback_t) throw(xHandlerNotSupported) {
 	throw xHandlerNotSupported(true);
 }
 
-bool cScrollbar::triggerClickHandler(cDialog& me, std::string id, eKeyMod mods, location where) {
+bool cScrollbar::triggerClickHandler(cDialog& me, std::string id, eKeyMod mods) {
 	// TODO: Implement detection of scrolling stuff, maybe even dragging the thumb
 	if(onClick != NULL) return onClick(me,id,mods);
 	return false;
@@ -131,7 +131,7 @@ bool cScrollbar::handleClick(location where) {
 	return clicked;
 }
 
-void cScrollbar::setFormat(eFormat prop, short val) throw(xUnsupportedProp) {
+void cScrollbar::setFormat(eFormat prop, short) throw(xUnsupportedProp) {
 	throw xUnsupportedProp(prop);
 }
 
@@ -139,7 +139,7 @@ short cScrollbar::getFormat(eFormat prop) throw(xUnsupportedProp) {
 	throw xUnsupportedProp(prop);
 }
 
-void cScrollbar::setColour(sf::Color clr) throw(xUnsupportedProp) {
+void cScrollbar::setColour(sf::Color) throw(xUnsupportedProp) {
 	// TODO: Colour is unsupported
 }