Scale web pages to fit
Don't update the URL field in webViewDidStartLoad, because the webView might still be holding the request for the previous page
Attempt to wipe all caches and cookies when the app terminates
If a directory cannot be deleted, recurse through its contents and attempt to delete them
Show a mask view in place of the browser when the app enters the background, to prevent snapshotting of the current web page
Only load the default page if the web view is empty when it appears