Fixes minor errors and refactors Service save method.
Fixes missing exception import
Adds multiple server errors support
Merges and solves conflicts.
Fixes test for unknown fields no longer expecting an exception from server.
Fixes minor issue on media validators
Ignores empty values on modifiers and type checks. (Required constraint must be used)
Adds url validator on Channel object
Fixes minor issues related with POST and PUT requests and exception messages
Minor fixes on multiple exception
Fixes Channel object tests
Fixes Media object tests