version compare and partial orgls

[Eric Dean Tribble <tribble>]

The unify operation does not (and should not) require that the orgl be
partial.  Two version of hamlet may be complete, but they can be
unified with each other (assuming they are equal).  

Note that just as for the version comparison operation, unification
doesn't care whether the orgl is partial or not:  it just unifies the
coordinate spaces, (but preexisting characters must be equal).

dean