Fixed video issues for latest iPhone models

- Update compatibility for iOS 9+
- Fix video playback in chapter views
- Updated text and image content in Valvular chapters
- Updated gallery table headings
- Convert to latest Swift version

Fixed image zooming/panning
Fixed incorrect image links

- Fix aspect sizing for enlarging pictures
 - Added poster picture for the movies embedded in chapters

Revamped UI for iOS 8
Flexible layout to adjust to user preferences
Bug fixes and optimizations
New App Icon