[ios8] - bugfixes for ios8 runtime

This PR fixes the following bugs we can see when running on ios8

1. Orientation of our layer is borked when compiled against ios8 sdk and running on ios8 runtime (apple finally fixed the 90° based coordinates)
2. Because of 1 orientation on external screen is messed up too when compiling against ios8 sdk and running on ios8 runtime
3. On ios 8 runtime (independend of used SDK) wthe textfield above the native keyboard is hidden
4. On ios 8 runtime (independend of used SDK) VTB hw decoder crashes on seek

This are all problems i have spotted on ios8 and i have tested all those changes on multiple sdk and runtime constellations. Definitly helix material.