Fix to share feature

Under the cover revision

Updated a few images.

* Added back button

* Fixed minor problems with iOS13

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

* Improved search and navigation
* Cleaner and faster interface
* Support for iPhone 6 and iPhone 6 Plus
* Almost 300 pages of additional bonus information on:
   - Survival Medicine (over 180 additional more in-depth pages)
   - Communications
   - Driving & Vehicles
   - Health & Fitness Calculators
   - Mountaineering
   - Navigation
   - Ropes and Lines Calculators
   - Tracking
   - Water Crossings
   - Water Rescue
   - Weather

* iOS6 and iPhone 5 Support
* Printing through AirPrint
* Send pages as pdf email attachments
* Improved Navigation and Favorites
* Search term highlighting

* Now fully supports iPad Retina displays.
* All new high resolution images for plants, animals, and insects.
* New interface and layout that is easier to read and navigate.

* Improved memory management and bug fixes

Version 2.0:
  * Support for both iPad as well as iPhone and iTouch
  * Improved search engine and navigation

Version 2.01
* Minor bug fixes for iPad version.
* Improved table of contents for iPad version.

* Now includes support for the new iPad as well as the iPhone and iTouch.
* Easier navigation with tap as well as swipe to change pages.
* Improved search with page excerpts.