Array.prototype.find and node < 4

[sigorilla]

Hi!

In package.json it is written that the plugin supports the version of node >= 0.10. But Array.prototype.find isn't supported for node <4.

List of files using find method:

1. style-prop-object 1
2. style-prop-object 2
3. no-children-prop

I think it's need to add polyfill or to drop support for node <4

[ljharb]

In order to retain eslint v2/node 0.10 compat, this definitely needs to be fixed.