revised the angle distance popover
defined a preliminary protocol object
Tried to make the Angle Distance settings work like the settings app
trying unsuccessfully to resize the popover
fixed seque to AngleDistance ViewController
added UITextField validation
used text fields to calculate new observation point
Major improvements/refactoring of Angle/Distance VC
Trying to fix the popover resize event
Cleanup public API, support model or NSDefaults
Support callback on sub VC, and finally fixed resizing issues
Added color to Angle/Distance
Disable tap outside popover when settings VC is shown
ensure only one angle distance popover is displayed.
block second+ maps popover