FastTimer: add the "paused" state and the pause/resume actions
FastTimerService: add support for unscheduled execution
FastTimerService: rename postsource to preevent
FastTimerService: do not duplicate plots so that they can be summed over nodes with the same number of processes
FastTimerService: add test file
Merge pull request #1860 from fwyzard/FastTimerService_part2

HLT update -- add to the FastTimerService support for unscheduled execution