Ing integration

This PR contains all the necessary files for the ING Direct integration: code, and the images of each number. It tries to minimize the number of requests, and the number of headers used.

In ING Direct, a form to introduce DNI and birthdate is showed, and then it redirects to a virtual keyboard to introduce the password's positions asked, so it's necessary to compare images to detect the numbers' order. Due to this, this integration have a dependency with RMagick.
We shouldn't print anything to the standard output by default, as this is not the CLI.