Workaround blurry fonts in main menu

@dinhviethoa

A workaround to eliminate the flickering or persisting blurry fonts in the menu (presumably slower machines were more susceptible to this).

1) Remove animations for the main menu.
2) Switch from using non-1.0 opacity to a no-op scaleZ(1) to form a stacking context from the overlay. This itself didn't fix the issue with animations different from "none", but this non-1.0 opacity wasn't helping anyway.