updated the img src to be used in marker-cell for each playlist
updated index.html.erb to display legendAndsources properly
updated List.js to display marker icon
added imageLocationUrl and playListMarkerIconLocationUrl
Merge branch 'master' of https://github.com/cburgos/playlist-storytelling-template-js
Merge branch 'master' of https://github.com/cburgos/playlist-storytelling-template-js
Merge pull request #1 from ginazhang/master

changes made to UI