Refactor observer synchronization to pull mode#256

Merged

auxten merged 3 commits intodevelopfrom

feature/pull_mode_observer

Feb 18, 2019

Commits on Feb 18, 2019

Refactor observer to pull mode
Qi Xiao
committed
Fix bug of observer restart recover
Qi Xiao
committed
Add comments for count in ObserverFetchBlock rpc
Qi Xiao
committed