Switch back to old school layout

It's confirmed that using `-layout` implicitly turns on constraint based layout and converts autoresizing masks to constraints, which kills performance, breaks layouts, and is often difficult to debug. This PR converts all of our usage of `-layout` back to old school stuff like `-resizeSubviewsWithOldSize:` and also replacing manual layout with autoresizing masks where possible.

The one thing I'm not happy about right now is resorting to the `-btr_layout` method to trigger relayout, which doesn't function like the `needsLayout` flag and executes the layout code immediately instead of waiting until the end of the runloop. This is something that could be improved upon by adding a non-AL replacement to `-layout` to `BTRView` at some point in the future.