Convert some idioms over to py3k-compatible idioms

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.