dagolden

Broad decisions about rationalizing version object behavior based on
discussions at the Lyon QAH.  Participants: David Golden, Ricardo Signes,
Karen Etheridge, Leon Timmermans, Peter Rabbitson and Graham Knop

- version comparision should be done irrespective of the presence of
  underscores in the string used to initialize the version object

- underscore should no longer be used as a tuple separator in vstrings or
  vstring-like strings; vstrings are converted to tuples by splitting into
  *characters* (not bytes) and converting to codepoints; any elements after