[OPEN-ILS-DEV] More unicode patches for SIPServer

[Dan Scott]

I offer two more patches (being used here in production at Laurentian
University) for SIPServer:

1) Takes a bit more care in using decode_utf8() / encode_utf8()
consistently; the generally recommended approach is to decode input and
encode output. 

2) Restore the old OpenNCIP checksum algorithm for handling Unicode over
the wire. This algorithm is necessary for our 3M V-series self-check to
work with the Unicode encoding enabled on the unit; I rather
painstakingly worked it out in late 2009 and submitted it to OpenNCIP
back then.

I have also attached "test_checksum.pl" to demonstrate the
observable difference between the old checksum and the new (I suppose
the right thing to do would be to roll this into the actual unit tests,
if there is general agreement that the checksum matches the reality of
more than just 3M V-series self-checks with Unicode encoding enabled).

If we discover that the Unicode checksum-handling differs between
various self-checks, then we may need to add yet another configuration
file option (sigh) to enable switching between the appropriate
algorithms. But hopefully %16C just works :)