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
Split out and rename STValidation
Split out and rename STBlob
Split out and rename STAccount
Split out STPathSet
Split STVector256 and move UintTypes to protocol/
Rename to STBase
Rename to STLedgerEntry
Rename to SOTemplate
Rename to STTx
Remove obsolete AgedHistory
Remove types.h and add missing includes
Remove unnecessary includes in app.h
Remove unnecessary includes in app.h
Remove include app.h from app1.cpp
