Inside dep_zapdeps(), detect cases such as || ( foo:1 foo:2 ), where we want

Inside dep_zapdeps(), detect cases such as || ( foo:1 foo:2 ), where we want
to prefer the atom which matches the higher version rather than the atom
furthest to the left. Sorting is done separately for each of choice_bins, so
as not to interfere with the ordering of the bins. Because of the bin
separation, the main function of this code is to allow --depclean to remove
old slots (rather than to pull in new slots).

svn path=/main/trunk/; revision=14626