Directive definition in a variable

[noppa]

Adds implicit annotation support for directive definitions
that are returned from a variable.

angular.module('MyMod').directive('foo', function() {
  var directive = {
    // Ctrl wasn't annotated before, but will be now.
    controller: function Ctrl(FooService) {},
  };
  return directive;
});

Currently, implicit annotations only work for a directive if the
directive definition is returned as an object literal.

angular.module('MyMod').directive('foo', function() {
  return {
    // Ctrl is correctly annotated.
    controller: function Ctrl(FooService) {},
  };
});

We have used the former quite a lot in our codebase, so we
needed to add support for it. I understand that the general
recommendation for more complex use cases like this is to add
explicit annotations, but here's a PR for the feature anyway
if you are interested. All the tests pass and I added one more
to test this specific case.

[schmod]

Looks good to me! Thanks for the contribution!

[noppa]

No problem, thanks for the awesome plugin!