Update downloads.md
Update downloads.md

Update Python 2 links to 2.7.7
Merge pull request #15 from Poorchop/patch-1

Update downloads.md
Update downloads.md

Update links to Python 2.7.8
Merge pull request #16 from Poorchop/patch-1

Update downloads.md
Tweak images.

Make the images responsive, class adopted from Bootstrap.