Allocate final tag versions on the go instead of preallocating versions [1 .. N].

Allocate final tag versions on the go instead of preallocating versions [1 .. N].

One cannot rely the fact that final versions are [1 .. N] anyway (they are renamed
during tag optimization), so this is not convenient as it seems.

Now versions start from 1, which looks better (more logical) on the pictures.