Improvements
2017 07 24
* new concept: drawing on big hidden 2x sized image for better resolution
* zoom (2x) picture is a direct copy of the 2x image with high quality
* zoom also has hints
* some errors removed.
- the backgrounds of Australia and Japan are not hiqh quality but extended only.
2017 07 15
* SUN position works on full size GREAT CIRCLE
* Azimuth and distance also displayed on zoomed window.
* WSPR lines now work also when the center is receiver.
       Displayed in the hint as DX with "call Tx"
2017 07 11:
* Magnifier 2x Zoom with doubleclick on the canvas (Great Circle)
  to an extra "dialogue window" without a dialogue.
* Lomger memory on the input line.
2017 12 11:
* Renamed to GCcalc for Great Circle calculator
  LOCcalc is another app by another developer
