Fix (?) restoring from state on iPad in landscape with no sidebar and no "show sidebar" button.
Switch to SVWebViewController and drop DZNWebViewController.

Too many crashes and finicky behavior from DZNWebViewController. Bye.

SVWebViewController handily comes with UIActivity subclasses for "Open in Safari" and "Open in Chrome", so that means goodbye ARChromeActivity and TUSafariActivity as well.
Let's try to see what's going on in CachePruner crashes.

Maybe it's running after the store is torn down. We should be cancelling it then anyway.