Subcomponent testing

Adding basic file creation tests for subcomponents (component in a pre-existing app).

To get this to work, I had to move the `config.save` (where `.yo-rc.json`) gets created, out of the `end` handler, as it wasn't being written in time to be found by the `derby:component` call. should have no impact on a non-robotic user.

Also, incidentally, fixing the lint command in `npm test`... though it's not using the local `.jshintrc` for some reason, which is weird... but didn't feel like incurring lintpocalypse for this PR.