(svn r21270) -Doc: Doxyment updates and additions. Removal of doxyment in code.

src/viewport_func.h

@@ -40,6 +40,12 @@ void ZoomInOrOutToCursorWindow(bool in, Window * w);
 Point GetTileZoomCenterWindow(bool in, Window * w);
 void HandleZoomMessage(Window *w, const ViewPort *vp, byte widget_zoom_in, byte widget_zoom_out);
 
+/**
+ * Zoom a viewport as far as possible in the given direction.
+ * @param how Zooming direction.
+ * @param w   Window owning the viewport.
+ * @pre \a how should not be #ZOOM_NONE.
+ */
 static inline void MaxZoomInOut(ZoomStateChange how, Window *w)
 {
 	while (DoZoomInOutWindow(how, w)) {};