amend policy insert_acct_class/acct_unique to work with multiple Class attributes

[jimdigriz]

Some deployments may wish to use multiple Class attributes and continue to use FR's existing provided accounting policies.

We also take the opportunity to remove needless hex encoding on the Class attribute due to the string to octet conversion originally in place; halving their length.

[alandekok]

My one question is does this change any existing behavior? If so, it would have to be added as a separate policy.

[jimdigriz]

Only problem I can foresee is when someone updates to this alternative policy and they have existing old hex encoded Class attributes out there in the wild coming in on the Accounting-Request's.

So maybe the 'encoder' is good, but for the 'decoder' we need to check if the preamble is either hex("ai:") or if it is hex(hex("ai:")) to determine what to do with it.

[alandekok]

Thanks, I'd be happier with being compatible with existing systems. I have a large fear of breaking peoples networks.

[jimdigriz]

Sorry it took a while, but I think the functionality to maintain backwards compatibility now works.