Handle non-object in 'json' RPC method
Clean up the checkAccept path to use the ledger sequence
Replace a lock with an atomic in new pathfinding
Clean up 'destination_currencies' in new pathfinding reply
Remove extraneous logging
Revert d2953f602eeee759e3e1c5a4d3a00ba51c5349a0
Support AccountTxnID and LastLedgerSequence.
Add directory and order book iterators
This should fix the crossed order book bug.
* Change OfferCreate::takeOffers to use new iterators
* Change NetworkOps::getBookPage to use new iterators
* If we find an offer in the book but not the ledger, deindex it
Add DeliveredAmount to transaction metadata
Never allow a retry as a final result
Pairwise no ripple:

* Cannot set noRipple flag with negative balance.
* Paths with consecutive no ripple links are invalid
* Adjust pathfinding value of no ripple out paths
* Check for no ripple when adding links in pathfinding
* Remove old noRipple logic
* Update trust line delete logic
Set version to 0.21.0
Prevent infinite loop in getBookPage
Temporarily change getBookPage not to use OB iterators
Set version to 0.21.0.rc1
Fix "limit" mishandling in doBookOffers
Whitespace changes
DirectoryEntryIterator fix
Set version to 0.21.0.rc2