Template based selection for enhancedobjectrelation

As I had mentioned here I have been thinking about enabling custom designs for the edit part of enhancedobjectrelation. I now added two more selection modes that use a new node/view/enhancedobjectrelation.tpl view (which by default simply redirects to line view) providing for easy overriding for other classes.

As a proof of concept, I added an override for the image class. It's definitely much friendlier to actually SEE what image one just selected ;)