[BUGFIX] Continue to use jQuery in Ember 2.x scenarios

[cibernox]

It turns out the default blueprint for addons generates an addon whose 2.X scenarios in ember-try fail by default.

In ca68ba3#diff-d2dc84345b41f0668236a56410bcc7bc addons began to be tested without jQuery by default, which is great, but in Ember 2.X we also need to install the ember-native-dom-event-dispatcher.

I still suspect this may not help the tests for Ember 2.12, but let's start from here.

[rwjblue]

This is looking good, I'd like to get this targetted at beta branch (which will require you to update the PR target and drop out any additional commits that are on master where you forked from and beta).

Also, can you confirm if we do or do not need to also add @ember/jquery to each of these 2.x scenarios? It seems to me that we should have it in there, but I just wanting to make sure we don't emit warnings about it during these try scenarios...

[cibernox]

@rwjblue I added the @ember/jquery addon to those scenarios to silence the warning (although I think it would work anyway).

Rebased over beta.