Occbin: add various consistency checks for bind/relax tags

In particular, emit more explicit error messages in the presence of
inconsistencies.

Closes: #103

preprocessor @ ef3609b6

-Subproject commit bb589042a94cf227a00756d7224949bff620acd9
+Subproject commit ef3609b6696c2e76ae30796c963025cd509f558d