use timeout of angular to be in the digist loop
if the tag found is of 0 size, try to look if it has one child that is
better (has an actual size)
SVY-6872 Element decorators
SVY-6874 show element margin in selection indicator

refactored soo that margin and resize knobs are a directive of there
own.
I guess resize can now go into the resizeknobs.js