more intuitive split view function.

[Mauxie14]

i switched to zen from arc and only found a few problems i personally had. one is that split view is not intuitive and hard to remember how and where you split screen. in arc you just drag the tab over another and splits it which is quick and intuitive

[Mauxie14]

it'd also be nice if when you split view something they aren't still shown as separate tabs but as one split view tab