Adding saturation control to Invert filter ; Splitting Mask and transparency effects...

Adding saturation control to Invert filter ; Splitting Mask and transparency effects submenu to a new Image effects, transparent submenu which contains all the previous effects except Eraser which is renamed to Light eraser and moved togheter with three new filters, Light eraser, negative, Monochrome positive and Monochrome negative to another new submenu called Transparency utilities