IE (certainly older versions) only accepts a genuine .ico file for the favicon, so I fixed it adding a 32x32 version at the same time for displays running at double the pixel density.
I wasn't sure of the font that the 'O' is written in but I think I got a pretty good match. If it's not up to scratch please let me know the font and I can adjust it.
This pull request effects the same changes as the one in master, but implemented slightly differently to accomodate the changes in 2.1 to how favicon is handled.
Updated favicon to be compatible with old versions of IE and also sup…
…port Retina displays