If width and height are set aspect-ratio has to be fixed

Before aspect-ratio was fixed only if cover was set to true but this
is wrong. Aspect-ratio should be fix if width and height are set. This
can be either by code (settings in image-component) or by user.
Merge pull request #220 from Ben-Ho/3.7-fix-crop-ratio

If width and height are set aspect-ratio has to be fixed