add/remove debug prints

Remove now unneeded debug printing statements and add some more for the
next release in pursuite of a solution to #2. Something weird seems to
be going on with right-shift.
don't pass reference to keys

Passing a hash ref to `keys` is a 5.14 feature, and is now considered
experimental, which causes it to produce warnings, which are fatal
with Test::NoWarnings.
Updated Changes
New CPAN release of Algorithm-AM - v2.43

    More debug printing
    don't pass ref to keys (experimental feature)