Update README.md
Make sure it doesn't break if images is empty or wrong
Merge branch 'master' of github.com:JMPerez/spotify-coverart

* 'master' of github.com:JMPerez/spotify-coverart:
  Update README.md
Remove small padding at the bottom of the image
Remove style that was adding padding at the bottom
Merge pull request #1 from rafeca/remove-padding-bottom

Remove small padding at the bottom of the image
Update LICENSE
Fix link
Update README.md
Change the structure following Polymer's conventions

Major refactor following instructions from Polymer site on
http://www.polymer-project.org/docs/start/reusableelements.html
Added demo