Fix for iOS 7.

The new date and time picker does not appear on a black background.
Fixing pull to refresh on iOS7.

Instead of assuming the content inset, we will add to and remove from it.
Merge pull request #191 from bholmes/ios7-fixes

Fix for iOS 7.
Turn one-line LICENSE to the actual license
Use UITableViewCell's appearance for StyledStringElement, issue 193