add episode db backend and store

appinfo/routes.php

lib/Controller/EpisodeController.php

lib/Controller/ShowController.php

lib/Db/Episode.php

lib/Db/EpisodeMapper.php

lib/Migration/Version000000Date20181013124731.php

lib/Service/EpisodeService.php

lib/Service/ShowService.php

src/App.vue

src/components/MediaHeader.vue

src/services/EpisodeApi.js

src/services/Player.js

src/services/ShowApi.js

src/store/episode.js

src/store/main.js

src/store/player.js

src/views/Episode.vue

src/views/Show.vue