fixed startup issues of Central and CentralPriorityScheduler
Merge pull request #247 from JWUST/feature/central_scheduler_fix

fixed startup issues of Central and CentralPriorityScheduler
TableScan becomes ParallelizablePlanOperation.
Merge remote-tracking branch 'origin/master' into feature/kh-tablescanpar
Revert "Fix some issues surrounding WITH_PAPI"

This reverts commit 90ccedfc113f796ae2c84a7b47beab29f74f4c1f.