Convert some idioms over to py3k-compatible idioms

• Import print_function from future and use print(..) instead of print ...
• Use repr instead of backticks when the object needs to be dumped, unless print(..) can do it lazily. Use str instead of backticks as appropriate for simplification reasons.

This doesn't fully convert these modules over py3k. It just gets over some of
the trivial compatibility hurdles.