add driver restart completed event
typo fixes
add restart completed handler to driver configuration
make restartcompleted extended time
typo fix
Merge branch 'master' of https://github.com/Microsoft-CISL/REEF into yingdac-restart-complete-handler
Merge pull request #972 from Microsoft-CISL/yingdac-restart-complete-handler

Add driver restart completed handler.

Tested on YARN and locally.