Perform layout with bounds and center instead of frame

[NickEntin]

Currently we perform layout by setting views' frames. Using frame for layout has some significant disadvantages. You can read about some of the complexity behind frames here. The most notable comes from this warning on the documentation for UIView.frame:

Instead of using frame to perform layout, we should instead set our views' bounds and center. This should have almost the same behavior as setting the frame, except in cases where the view has a non-identity transform (in which case the frame is undefined anyway). This also matches how Auto Layout behaves around transforms.