libopaque v1.0

This mature enough to release as v1.0

One tiny new feature is the unlink_masking_key mechanism, which ensures that all user records belong to the same threshold-setup are unique, and thus unlinkable. however the usage of 3hashTDH negates this, as the zero record makes them trivially linkable, by testing which zero record shares reconstruct to zero. So either you have 3hashTDH or you have unlinkable user records. can't have both. maybe, for now.

anyway. yay for v1.0 \o/