[dev] 4 verschiedene getDistance() in CWPoint

(1)public double getDistance (CWPoint dest)
(2)public double getDistance (double latDecD, double lonDecD)
(3)public double getDistanceRad (double latDecD, double lonDecD)
(4)public double getDistanceRad (CWPoint ll)

function MercatorToNormal(y: double): double;
begin
   y := -y * PI / 180; // convert to radians
   y := sin(y);
   y := (1 + y) / (1 - y);
   y := 0.5 * ln(y);
   y := y / (2 * PI); // scale factor from radians to normalized
   y := y + 0.5; // and make y range from 0 - 1
   result := y;
end;

function NormalToMercator(y: double): double;
begin
   y := y - 0.5;
   y := y * 2 * PI;
   y := exp(y * 2);
   y := (y - 1) / (y + 1);
   y := arcsin(y);
   y := y * -180 / PI;
   result := y;
end;

function WGS84toGOOGLE(lat, lon: double): MiniString;
var
   x, y: double;
   quad: MiniString;
   lookup: MiniString;
   digits: integer;
   i: integer;
begin
// now convert to normalized square coordinates
// use standard equations to map into mercator projection
   x := (180.0 + lon) / 360.0;
   y := MercatorToNormal(lat);
   quad := 't'; // google addresses start with t
   lookup := 'qrts'; // tl tr bl br
   for digits := 0 to 26 do begin
// make sure we only look at fractional part
      x := x - floor(x);
      y := y - floor(y);
      i := 1;
      if (x >= 0.5) then inc(i);
      if (y >= 0.5) then inc(i, 2);
      quad := quad + lookup[i];
// now descend into that square
      x := x * 2;
      y := y * 2;
   end;
   result := Quad;
end;

function GOOGLEtoWGS84(Value: MiniString; out lat, lon: double): boolean;
var
   x, y, Scale: double;
   i: integer;
   c: MiniChar;
begin
   x := 0.0;
   y := 0.0;
   scale := 1.0;
   Value := LowerCase(Value);
   for i := 2 to Length(Value) do begin // skip the first character
      Scale := Scale * 0.5;
      c := Value[i];
   //   q  r
   //   t  s
      case c of
         'q': ;
         'r': x := x + scale;
         't': y := y + scale;
         's': begin
               x := x + scale;
               y := y + scale;
            end;
      else
         Result := false;
         exit;
      end;
   end;

   lon := (x + scale * 0.5 - 0.5) * 360;
   lat := NormalToMercator(y + scale * 0.5);
   result := true;
end;