Fix to share feature

Under the cover revision

* Added back button

* Fixed minor problems with iOS13

1-General
Main image detailed
5-Airplane and Systems Descriptions
  5.7-Ground Control System
  5.8-Wing Flap System
Design improvements
App size improvement
64 bits compatibility

* Updated for compatibility with iOS 10 and above.
* Improved usability and sharing.

* Now with over 110 pilot calculators and over 80 pages of Weight and Balance
* Improved search and navigation
* Cleaner and faster interface
* Support for iPhone 6 and iPhone 6 Plus

* iOS7 compatibility
* Bug fixes

* Improved navigation
* Bug fixes
* Search term highlighting

Add-On Store
You can now purchase additional content within the application.  First two add-ons available are Aircraft Weight and Balance and Pilot Calcs  Try out the samples from each add-on!.

Printing
Now you can print a single calculator or the whole calculator tape to any AirPrint printer.

Improved Email
In addition to the standard email, you may now send any calculator or the whole calculator tape as a PDF file attached to an email.

iOS6 and iPhone 5
The app now supports iOS6 and also the new screen size on the iPhone 5.

Improved Navigation
Favorites can now also show the list of your most used calculators and those most recently used.

* Added the newly released Appendix: Runway Incursion Avoidance.

* Completely updated for retina displays with high resolution graphics.
* Over 60 aviation calculators - both standalone and integrated with content.
* Improved interface with better readability.
* Email any page.
* Built-in calculator.

* Improved memory management and bug fixes

* Fixed bug with showing subscripted text.

* Complete update of the book to the 2008 version with new content and graphics
* Now supports iPad as well as iPhone and iPod Touch
* Improved navigation and search functionality