Made auto ref work for non template functions.

This implements auto ref parameters for non template functions so that local variables are created when the function is called with rvalue arguments, as discussed in [this newsgroup thread](http://forum.dlang.org/thread/mailman.2989.1356370854.5162.digitalmars-d@puremagic.com?page=2#post-rsjzbadnwzoetyeonhcz:40forum.dlang.org).