rounded square on long press action

#more_or_less_frivolous

in google calculator, the app which opencalc takes considerable inspiratiom from, the buttons turn smoothly into **rounded squares** from the regular ellipses upon *pressing or holding them*.


for the sake of consistency of design and idk sheer "fun" i thought it'd be nice to include that behaviour in opencalc too. again, it evidently adds nothing to the functionality and the app is totally fine without this feature but hey, it looks so nice that animation when tapping on the buttons, doesnt it??

alternatives? nahh the **rounded squares** are the only other shape in the material design catalogue so no. just the ellipses turning into **rounded squares** when holding the buttons

shoutout to darkempire78 for his inability to retain this small feature request and making me open an issue on the rep. see you next tuesday, 78!