Closes#488
- When sync process is finished cache DB is removed from disk.
- Latest downloaded block is preserved becuase it's required to computes
in which phase to resume sync process.
- `SDKSynchronizer.latestDownloadedHeight` public API is removed
it makes no longer sense. This API was reading from cache DB.
- blocking API removed, only latestBlockHeight() stayed
- non-blocking closure based API removed
- unit tests updated to use async API
[#492] Get rid of blocking API (#551)
- forgotten commented code cleaned up
- some comments were still mentioning result (completion closure), removed
Michal Fousek
Francisco Gindre
Kris Nuttycombe
Lukas Korba
Daniel Haight