Rename bx::swap to bx::xchg.

include/bx/bx.h

@@ -39,7 +39,7 @@ namespace bx
 #define BX_IGNORE_C4127(_x) bx::ignoreC4127(!!(_x) )
 
 	template<typename Ty>
-	inline void swap(Ty& _a, Ty& _b)
+	inline void xchg(Ty& _a, Ty& _b)
 	{
 		Ty tmp = _a; _a = _b; _b = tmp;
 	}