Add `-stopafterblockimport` option
Add `-stopafterblockimport` option

Stop after importing blocks. This can be useful for development
and trouble shooting.

(cherry picked from commit 1569353b8aa535f086833acb6223650972c89790)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin