Pixie and NiGui

[chrisecker]

Thanks for figuring this out. Colors are fine when I replace copyMem by the 
following code
    
    
    var nimage = cast[cstring](niGuiImageData[0].addr)
    var pimage = cast[cstring](image.data[0].addr)
    
    var j = 0
    for i in 1..(canvas.width*canvas.height):
      nimage[j] = pimage[j]
      nimage[j+1] = pimage[j+2]
      nimage[j+2] = pimage[j+1]
      nimage[j+3] = pimage[j+3]
      j += 4
    
    
    Run