Iterator THANKS file

Iterator has originally been written by Marek Rychlik.

Many people have further contributed to Iterator 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.

Mathematicians
--------------
Oliver Knill
Maciej Wojtowski
Thomas Spencer

Code
----
In the implementation of Iterator we used autotools-0.10 authored
Eleftherios Gkioulekas and GNU regex library (see the AUTHORS file in
the regex-0.12 directory and other files; this package in full is
available from prep.ai.mit.edu:/pub/gnu. We only used the code in
src/regex.[ch], so the documentation of regex is not included in order
to keep the size of this package down).
