- got rid of silly #define ..._BIT, #define ... (1<<..._BIT) stuff

- switched almost all uiDefBut(..., TOG|BIT|..) to use UiDefButBit and the
   name of the actual bit define instead of just a magic constant, this makes
   searching the code much nicer. most of the credit here goes to LetterRip
   who did almost all of the conversions, I mostly just checked them over.

source/blender/src/header_buttonswin.c

@@ -560,14 +560,14 @@ void buts_buttons(void)
 
 	uiBlockSetEmboss(block, UI_EMBOSSN);
 	if (curarea->flag & HEADER_NO_PULLDOWN) {
-		uiDefIconButS(block, TOG|BIT|0, B_FLIPINFOMENU, 
+		uiDefIconButBitS(block, TOG, HEADER_NO_PULLDOWN, B_FLIPINFOMENU, 
 					  ICON_DISCLOSURE_TRI_RIGHT,
 					  xco,2,XIC,YIC-2,
 					  &(curarea->flag), 0, 0, 0, 0, 
 					  "Show pulldown menus");
 	}
 	else {
-		uiDefIconButS(block, TOG|BIT|0, B_FLIPINFOMENU, 
+		uiDefIconButBitS(block, TOG, HEADER_NO_PULLDOWN, B_FLIPINFOMENU, 
 					  ICON_DISCLOSURE_TRI_DOWN,
 					  xco,2,XIC,YIC-2,
 					  &(curarea->flag), 0, 0, 0, 0,