Refactor ECDSA canonical checks
[FOLD] Fix typo
[FOLD/TX-REFAC] Transactor include guard fixup
[FOLD/TX-REFAC] WalletAdd Transactor journal
[FOLD/TX-REFAC] TrustSet Transactor journal
[FOLD/TX-REFAC] RegularKeySet Transactor journal
[FOLD/TX-REFAC] Payment Transactor journal
[FOLD/TX-REFAC] OfferCancel Transactor journal
[FOLD/TX-REFAC] Change Transactor journal
[FOLD/TX-REFAC] AccountSet Transactor journal
[FOLD/TX-REFAC] OfferCreate Transactor journal
[FOLD/TX-REFAC] OfferCreate cleanups:

 - Use std:: containers instead of boost::
 - Remove unneeded parameter shadowing member variable
 - Remove BOOST_FOREACH
 - Small cleanups
[FOLD/TX-REFAC] Begin documenting OfferCreate