Optimize reversed(range(...))

I thought this would be the best place to ask, is there an easy way to get a value out of a NameNode? Right now it only optimizes it, if it has a number literals within the range (e.g. `reversed(0, 5, 3)`) because I don't know how to do this.

I realized I should use floor div (`\\`) because Python 3+ returns a float on normal division.

Ticket #765.