Yandex (russian search engine) provider and user gender support

[kudmni]

No description provided.

[coveralls]

Coverage increased (+1.61%) when pulling e128fb8 on kudmni:master into 47d9447 on thephpleague:master.

[ramsey]

Thank you for your contribution.

This pull request includes too many changes across multiple providers. It is not just adding the Yandex provider. Please see our contributing guidelines, in particular:

• Create topic branches - Don't ask us to pull from your master branch.
• One pull request per feature - If you want to do more than one thing, send multiple pull requests.
• Send coherent history - Make sure each individual commit in your pull request is meaningful. If you had to make multiple intermediate commits while developing, please squash them before submitting.

Furthermore, we're working to pull providers out and make them into their own packages. I've just merged in a new PR that updates the AbstractProvider and provides more details in the README about extending AbstractProvider. Please take a look at the README and consider converting this work into a separate repo for the Yandex provider. Once you've done that, you may send a PR to update the README with a link to your provider.

Thanks!