Broadcast idtype fix

Expected: Antie Channel object to be created with 'type' set from the OIPF Channel object's 'idType' on HbbTV devices. Antie Channel object to be created with 'type' explicitly set to undefined on Samsung devices. Antie Channel object's 'type' property to be refactored to 'idType' to make it more explicit.

Actual: Antie Channel object is created with 'type' set from the OIPF Channel object's 'channelType' on HbbTV devices. Antie Channel object's 'type' not set by Samsung devices. 

Fix: Refactor 'Channel.type' to 'Channel.idType' in Antie. Change 'HbbTVSource' to use 'idType' from the OIPF Channel object created by the device instead of 'channelType', and change references to 'Channel.type' to 'Channel.idType'. Change SamsungSource to set 'idType' to undefined when creating an Antie Channel object, and remove the unused 'channelType' attribute in the construction of Channel.