revert 593cfc49ed5c5984e6f3da6899c06888b4ea6217
Initial support for anti-stampede callbacks in Execution Filter, refs #668
More stampede protection callback work: also trigger started callback when readCache() failed, and only trigger finished callback when something was written (otherwise the second call which initially works on stale data kills the flag right away!), refs #668
Fixed #670: Actions that return no View are never cached.
merge 463da7fe42e05975c00c24f7e4afe9fb04d89fec to b663f76a3d3fe1b8f23e67d307586d5af9da75d9 from 0.11