Add proper sorting of numeric plist keys

Frameworks/plist/src/to_s.cc

@@ -166,11 +166,18 @@ namespace
 				return true;
 			else if(rhsIter != _key_ranks.end())
 				return false;
+			else if(is_numeric(lhs.first) && is_numeric(rhs.first))
+				return std::stol(lhs.first) < std::stol(rhs.first);
 			else
 				return lhs.first < rhs.first;
 		}
 
 	private:
+		static bool is_numeric (std::string const& str)
+		{
+			return str.find_first_not_of("0123456789") == std::string::npos;
+		}
+
 		std::map<std::string, size_t> _key_ranks;
 	};