remove series referenceproperty
Merge branch 'master' of https://github.com/GoogleDeveloperGroups/devfest-site
add gadc13 content
Merge branch 'master' of https://github.com/GoogleDeveloperGroups/devfest-site
Merge branch 'master' of https://github.com/GoogleDeveloperGroups/devfest-site
Merge branch 'master' of https://github.com/GoogleDeveloperGroups/devfest-site
rebranding devfest to devfestw, no use of series anymore
merge