Jsonrewriter: balance_change type includes xrp balance
Jsonrewriter: added 'fee' effect type
Jsonrewriter: add balance_changer indicator
Jsonrewriter: fee effect should also have a balance field
Jsonrewriter: Separate fee from balance_change
New history page. See #347. Fixes #522, fixes #763, fixes #718.
Differentiate sell/buy offers by tfSell flag