update to wiggle hydra example

I decided to add frequency into my wiggle hydra example. Frequency adjusts the distance between a wave making wider or shorter waves. The old one only let you change the amplitude of the wave on the x and/or y.

kernel morph
{

parameter float xangle< minValue: 0.0;
    maxValue:10.0;
    defaultValue:5.0;
>;
parameter float frequency< minValue: 0.0;
    maxValue:2.0;
    defaultValue:1.0;
>;
parameter float yangle< minValue: 0.0;
    maxValue:10.0;
    defaultValue:0.0;
>;

    void evaluatePixel(in image4 src, out pixel4 dst)
    {
        float2 coord = outCoord();
        float xcoord = coord.x - sin(coord.y*frequency)*xangle;
        float ycoord = coord.y - sin(coord.x*frequency)*yangle;
        dst = sampleNearest(src,float2(xcoord,ycoord));
        if(dst.r==0.0&&dst.g==0.0&&dst.b==0.0){
           dst = sampleNearest(src,outCoord());
        }
    }
}