* Support PreviousTxnID until the switchover
* Implement "No Ripple" for issue_iou and redeem_iou.
* Do not utilize issue_iou and redeem_iou from legacy code
* Rename 0.27.x legacy files to account for VS build process
* Misc. cleanups
The PreviousTxnID field has been deprecated and should not be used for
transactions that use the field will now be rejected.
The AccountTxnID feature should be used instead by enabling transaction
tracking and specifying a transaction ID at submission. More details
are available at: https://ripple.com/build/transactions/#accounttxnid
An alternative to the unity build, the classic build compiles each
translation unit individually. This adds more modules to the classic build:
* Remove unity header app.h
* Add missing includes as needed
* Remove obsolete NodeStore backend code
* Add app/, core/, crypto/, json/, net/, overlay/, peerfinder/ to classic build
* New src/ripple/crypto and src/ripple/protocol directories
* Merged src/ripple/common into src/ripple/basics
* Move resource/api files up a level
* Add headers for "include what you use"
* Normalized include guards
* Renamed to JsonFields.h
* Remove obsolete files
* Remove net.h unity header
* Remove resource.h unity header
* Removed some deprecated unity includes
