Add patchClassicComponent option to avoid deprecation warnings

[mydea]

To opt-in to address #709 until a breaking release is made.

This would allow you to specify:

  let app = new EmberAddon(defaults, {
    'ember-test-selectors': {
      patchClassicComponent: false
    }
  });

To avoid including the patch at all, thus avoid the deprecations if you do not use classic components (or the bindings on classic components, at least).