No hidden parts in Buzzy versions

We were being a bit muddled with “hidden” parts in a Buzzy version
string.  That's how I had originally planned on handling the `dev4` <
`dev10` problem.  But now I have all of the foo-to-Buzzy version
converters explicitly break apart that into separate parts: `dev.4` and
`dev.10`, which were compared correctly before.  So no more hidden parts
at all.  You can always directly see in a Buzzy version the parts and
how they'll compare.