Improve debug logging of rlm_perl

Don't just show the attributes being copied, but also say where they are
copied from/to.
Merge pull request #714 from qnet-herwin/perl_more_debugging

Improve debug logging of rlm_perl
Fixup debugging and formatting in rlm_perl
Rename vpsname to list_name

Add array indexes to multivalued attributes
Convert binary values to octets type attributes correctly
Use standard return codes