Fix cropping when using high resolution images

When you upload high resolution image, the cropping goes wrong.

It can be seen when you use image from http://placehold.it/1600x800.

To solve this, we have to use "Box Sizing method" of JCrop.

boxWidth: boxSize, 
boxHeight: boxSize,

At the same time, bootstrap auto scales the image and we have to disable it for the image on which we apply Jcrop:

#files img{
  width: auto;
 max-width: none;
}