Use drawViewHierarchyinRect when applicable

[HighKo]

This request has 2 purposes:

1. Avoid crashes in iOS 9 when -renderInContext is called at this point
2. Increase performance, when -drawViewHierarchyInRect is available

[mrackwitz]

This reverts this change here, which is sadly poorly documented. Overall this has a lot of edge cases and needs some manual testing on device with orientation changes and e.g. navigation controller animations. But if it is still currently crashing, than it is unlikely, that even if that would be a regression, it will be fixed soon.