Attempt at fixing Mac Clang build that I broke with my previous changes to metalloprotein handling.
--I think I had bad dependencies -- something from core.3 depending on something from core.4. I've moved all the metalloproteins utilities to core/util/metalloproteins_util.cc, which is in core.4.
--I have no idea why the build was working under Linux, though (with both gcc or Clang).
Unit test status: Pass
Integration test status: Not Run
--I don't have access to a Mac with Clang right now, so I'm relying on the test server to tell me whether this works. Everything compiles fine on my Linux PC with gcc, though everything did before, too.