Fix to share feature

Under the cover revision

* Added back button

* Fixed minor problems with iOS13

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

* Added 15 fitness-related calculators
* Improved search and navigation
* Cleaner and faster interface
* Support for iPhone 6 and iPhone 6 Plus

* Improved navigation
* Bug fixes
* Search term highlighting

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

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.

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

* Support for iPad 3 retina display
* Color photos for many techniques
* Higher resolution graphics for many pages
* Improved memory management and paging
* Send any page by email

* Improved memory management and bug fixes

* Now supports iPad as well as iPhone and iPod Touch
* Improved navigation and search