Added is_cacheable traits structs.
Replaced boost lexical_casts with std equivalents.
Prevents same/different values being stored with a given key, [Finish #23995996].
Added some error codes for Passport.
Added final error codes for Passport.
Merge remote-tracking branch 'origin/prevent_kvb_duplicates' into vault
Added initial NFS error codes and category.
Further NFS error_code addition.
error cast fixed
Added per-library error classes derived from system_error.
Updated projects in log.cc
Fixed boost build error.
removed .has_exception use
Fixed missing comma.
Added anothe NFS error value.
Added another couple of Passport error values.
typo
Exposed CryptoPP::Integer.  Added is_payable default trait.
additional error code [#26111577]
Another nfs error code entry.