add comment giving credit to the authors of Python's Decimal
add comment giving credit to the authors of Python's Decimal

git-svn-id: 8ad740ae658cd92c822f58141ca589f831050ce3@38 adf89df5-a3c0-4ca2-a202-d6f62979bbc9

jgoizueta/flt,jgoizueta/ruby-decimal