Implement list swiping with animation

[jhasenzahl]

The original swiping implementation was buggy due to relying on x/y gesture velocity values, and conflicts with pressing or long pressing a task.

Need to re-implement properly to rely on comparing to a pre-recorded "swipe" gesture rather than on velocity values. Will also need to re-implement press/long-press to be more compatible with swiping.

Swiping should also cause a neat animation of a new list taking the place of the old one. This will require some research as I have no idea how to do it yet.