Make decisions one way or the other on converting additional class imports to proper ODK imports

[hoganwr]

Besides issues #249, #250, #251, and #252, we have classes from the following ontologies that could be converted to proper ODK import. We need to decide, for each one, whether to do it and the priority (the ones for which issues already logged are top priority):

1. OBI
2. DOID
3. PATO
4. UBERON
5. VO
6. UO
7. FBCV

[hoganwr]

OBI was made a separate import in ODK in #274