Create CropResizer.php

This is a new resizer for SonataMediaBundle. It works in any case without deforming the original ratio of the image, but when there are big differences in the image dimensions it resizes original image to the one of the dimensions of the output image and crops the output image from the middle of the resized image.
Me and the team that I am in used this piece of code in the http://casecom.bg .