Bug fixes and updates

- HomeResponseMaker now calls a list of active channels to populate the
channel feed. Previously this was a config setting
- ArticleRepository get map items now respects is_approved
- New ChannelRepository method to retrieve a list of top level channel
ID’s
- Rework cinemaListingTransformer to sort by performance start date
- EventTransformer now provides the lowest possible from price
- ShowTimeTransformer method to sort performances and return a lowest
possible price
- Removed homeChannel config item from global.php