wrap "gapi" calls with $q.when

[orizens]

that - in order to avoid injecting $scope/scope.
in uGapi:

function insert (params) {
                return $q.when(gapi.client.youtube[resourceName].insert(params))
                    .then(function (response) {
                        return response;
                    });
            }

then, other services/controllers don't need to use $scope.$apply (like in UserPlaylists).