Setting dropChannel does not work

[mhuttner]

There seems to be an issue with the $observe statement in Line 130

attr.$observe(attr.dropChannel, function (value) {
  if (value) {
    dropChannel = value;
  }
});

should be

attr.$observe('dropChannel', function (value) {
  if (value) {
    dropChannel = value;
  }
});

in Order to set the Channel correctly.

Thanks!