Add tasks for all the new languages

Task/Grayscale-image/Lingo/grayscale-image.lingo

@@ -0,0 +1,19 @@
+on rgbToGrayscaleImageFast (img)
+  res = image(img.width, img.height, 8)
+  res.paletteRef = #grayScale
+  res.copyPixels(img, img.rect, img.rect)
+  return res
+end
+
+on rgbToGrayscaleImageCustom (img)
+  res = image(img.width, img.height, 8)
+  res.paletteRef = #grayScale
+  repeat with x = 0 to img.width-1
+    repeat with y = 0 to img.height-1
+      c = img.getPixel(x,y)
+      n = c.red*0.2126 + c.green*0.7152 + c.blue*0.0722
+      res.setPixel(x,y, color(256-n))
+    end repeat
+  end repeat
+  return res
+end

Task/Grayscale-image/Phix/grayscale-image.phix

@@ -0,0 +1,15 @@
+function to_gray(sequence image)
+sequence color
+    for i=1 to length(image) do
+        for j=1 to length(image[i]) do
+            -- unpack color triple
+            color = sq_div(sq_and_bits(image[i][j], {#FF0000,#FF00,#FF}),
+                                                    {#010000,#0100,#01})
+            image[i][j] = floor(0.2126*color[1] + 0.7152*color[2] + 0.0722*color[3])*#010101
+        end for
+    end for
+    return image
+end function
+
+sequence img = read_ppm("Lena.ppm")
+    img = to_gray(img)

Task/Grayscale-image/Sidef/grayscale-image.sidef

@@ -0,0 +1,19 @@
+require('Image::Imlib2')
+
+func tograyscale(img) {
+    var (width, height) = (img.width, img.height)
+    var gimg = %s'Image::Imlib2'.new(width, height)
+    for y,x in (^height ~X ^width) {
+        var (r, g, b) = img.query_pixel(x, y)
+        var gray = int(0.2126*r + 0.7152*g + 0.0722*b)
+        gimg.set_color(gray, gray, gray, 255)
+        gimg.draw_point(x, y)
+    }
+    return gimg
+}
+
+var (input='input.png', output='output.png') = ARGV...
+var image = %s'Image::Imlib2'.load(input)
+var gscale = tograyscale(image)
+gscale.set_quality(80)
+gscale.save(output)