This commit gets the tests passing for labs as well. The required
changes:

1. Add code_systems and code_system_names back into the generated JSON
2. Fix some values in the expected JSON which were incorrect (perhaps an
   old bug meant we truncated decimal points on values?)
3. Remove reference_range from the expected JSON, since CCDA labs don't
   actually parse it yet.
Adds reference range parsing into CCDA labs and updates the tests
accordingly. Now the JSON fields for C32 and CCDA labs should be
equivalent.
error in readme