OPARI2 THANKS file

OPARI2 has originally been written by authors in AUTHORS file. Many
people further contributed to OPARI2 by reporting problems, suggesting
various improvements or submitting actual code. Here is a list of
these people. Help me keep it complete and exempt of errors.

Chee Wai Lee <cheewai1972@gmail.com>
Hendryk Bockelmann <bockelmann@dkrz.de>
Orion Poplawski <orion@cora.nwra.com>
Piero Lanucara <p.lanucara@cineca.it>
Aleksandr Drozd <alex@smg.is.titech.ac.jp>
Sally Bridgwater <sally.bridgwater@nag.co.uk>
Xavier Le Vaillant <xavier.levaillant@serviware.com>
Samuel Thibault <samuel.thibault@ens-lyon.org>
