add support for dot notation

[jelhan]

• add basic support for dot notation
• support usage of dot notation in a nested object, e.g. { "foo": { "bar.baz": "..." } }

[snewcomer]

@jelhan Phenomenal! I'm guessing you have tested this out on your own app(s) and it worked?

[jelhan]

I tested mostly with the data in dummy/ directory. If run these steps to ensure that actual data and expected data are the same:

cd dummy
node ../bin/ember-i18n-intl-migrator.js --type=yaml
git status

Maybe we should setup TravisCI to run yarn test and something similar to instructions above? Could provide in another pull request if you like.

I've also tested with https://github.com/jelhan/croodle, which I need this for. But wasn't yet able to fully test cause some addition transformations need to be done manually (e.g. missing support for value invocation with 3-curlies to skip HTML escaping). Feel free to wait with merging this one until I could confirm that it helped me with the real-world scenario.

[snewcomer]

Ok I'll wait for you to test on your real world scenario!

[jelhan]

Was able to migrate my translations. Faced an edge case that I needed to fix manually:

export default {
  'foo': 'parent',
  'foo.bar': 'child',
}

This can not be transformed to YAML or nested JSON objects as the value of foo should be a string ("parent") and an object ({ bar: 'child' }) at the same time. The codemod does not warn in such a case. To be honest I was to lazy to add such a warning. I don't expect many people to use this codemod as hopefully most apps already migrated.

Ready to be merged from my side.