It looks like April is the month for major Android apps to get a visual overhaul. Following Twitter's refresh last week (and Facebook's decidedly more ambitious effort), Tumblr has today released its own app update that offers a whole new user interface. As you can see above, that includes some Path-esque expandable controls for creating various types of posts, as well as new post animations and a general appearance that's more consistent with Android's "Holo" theme. There's no indication yet of that new interface heading to iOS, which just got its own Tumblr update last month.