Minor formatting updates to support new iPhone display sizes.

App meta data updates, no changes to code.

Code updated to be compliant with the latest version of iOS.

Updated to latest Apple OS and development environment.

Rebuild to ensure compliance with iOS version 12.1.

Minor compatibility code changes for iOS 11 and Xcode 9.

A calibration function for pitch (portrait mode) and roll (landscape mode) has been added. Calibration is accessed through the menu. Instructions are on the Help page. Calibration is simple: 1) Place the back of your iPhone on a verified true-vertical surface, 2) Press the Reset Bias button, 3) Press the Save button, 4) Rotate the phone to landscape orientation and do steps 1 through 3 again. The pitch and roll biases you save will be used as offsets to the iPhone's pitch and roll values. For newer phones this feature may not be needed. But for older phones, like the iPhone 5 and 5s, that used older motion coprocessor chips, it has been reported that pitch could be off by a degree or two. Other changes: Use of quaternions to isolate pitch and yaw for better accuracy, and a few cosmetic changes.

Display update performance improvements. A new Settings view allows a Fast Updates option to be turned on or off. When ON, display updates every 1/10 of a second. When OFF, display updates at the default rate - every 1/2 second.