[osis-core] Names for the versification systems

[Todd Tillinghast]

Kees,

In Paratext there are standardized reference systems that are referred
to by number (1-5 I believe).  We talked about adopting the UBS set of
reference systems in the January meeting.

Could you send us the "names" of these reference systems for
consideration relative to designating "standardized" values for the
<referenceSystem> element in <work>?

Todd