CLC-3410 Move CalLink proxy files to new models dir
CLC-3410 Rename CalLinkMembershipsProxy->Memberships and CalLinkOrganizationProxy->Organization
CLC-3410 Put CalLink proxies into CalLink module
CLC-3410 Rename CalLinkProxy->Proxy
CLC-3410 Move video classes into app/models/webcasts
CLC-3410 Rename PlaylistsProxy->Playlists and YoutubeProxy->Youtube
CLC-3410 Put video classes into Webcasts module
Merge pull request #2228 from ctweney/clc-3410-3

CLC-3410 Third batch of proxy reorg: Webcasts