fix setting format flags in Window::operator<<(Format)

I though static variables are created for each class object,
but apparently they aren't, which makes the previous design
utterly broken. I'm suprised it somehow worked before.

src/window.h

@@ -195,6 +195,10 @@ namespace NCurses
 			
 		private:
 			std::deque<std::wstring> *itsHistory;
+			
+			int itsBoldCounter;
+			int itsReverseCounter;
+			int itsAltCharsetCounter;
 	};
 }