Adding MvcImageResize.php. This will now allow for adding an unlimited number or images sizes using the standard
WordPress function add_image_size(). Instead of generating the cropped versions for each image, this will
instead only crop the ones when used. For instance is you have a blog feed with a special image sized thumbnail
This will allow for only crating the thumbnail for the ones which show up in the feed.

Also added a couple additional methods to the main framework class

Signed-off-by: lipemat <mat@matlipe.com>