Make img own the list of source sets. Fixing #89
Specify the media attribute. Fixing #98
Remove bogus use of the term 'fallback content'. Fixing #88
Merge pull request #104 from zcorpan/fix-98

Specify the media attribute. Fixing #98
Merge pull request #102 from yoavweiss/gh-pages

Generated index.html after marcosc's PR
Merge pull request #105 from zcorpan/fix-88

Remove bogus use of the term 'fallback content'. Fixing #88
Merge pull request #103 from zcorpan/fix-89

Make img own the list of source sets. Fixing #89
Regenerate spec after zcorpan's PRs