Support custom localisation and other yadda options

[karoluck]

At my work we're using fork of ember-cli-yadda everyday in cooperation with architects. There are already only 2 missing functionalities in this plugin which we need to use original plugin (BTW thanks for adding @ignore annotation, that is what we've also needed). I mean:

• Support custom localisation (Our achitects are writing tests in our native language)
• Support another yadda options

Our fork of ember-cli-yadda has hardcoded FeatureParser initialization, it looks like that:

var feature = new yadda.parsers.FeatureParser({
  language: yadda.localisation.Polish,
  leftPlaceholderChar: '<',
  rightPlaceholderChar: '>'
}).parse(content);

We need also possibility to change square brackets into angle brackets for using variables due to cooperation also with PHP Team. They are using Behat, and there are angle brackets for using variables behat docs. We've decided to be consistent with PHP Team.

With this PR changes we will be able to set custom yadda config in our app environment config by adding:

ENV.APP.yadda = {
  language: 'Polish',
  leftPlaceholderChar: '<',
  rightPlaceholderChar: '>'
};

So here is my PR which should resolve our problems and allows us to use official version of ember-cli-yadda. I'm open to any suggestions if it needs some improvements.

I wanted to write some tests, but it needs some tricky way to use custom acceptance tests directory. Because with custom configuration current tests will definetly fail (and thats correct, using another localisation, english tests can't work). I can add tests later in another PR (it really needs tricky way which i didn't want to include in this PR).

Note: this version of code is fully backward compatible.

[albertjan]

closed in favour of #72 thanks @dejavs