Fixing (hardcode) user app icons on the desktop uniformly

 * The fix scales icons that are larger and smaller than "kano" icons
 * It hardcodes their position as they are shifted to the bottom
 * Set GridIconWidth/Height to 124 and 132 to left kano icons untouched.
Merge pull request #53 from KanoComputing/custom-grid-alignment

Fixing (hardcode) user app icons on the desktop uniformly