add Pre- and PostModuleEventDelayedGet callback
update unit test output to reflcect changes to the Tracer service
Fixed sending DelayedGet signal for getByToken

The call path taken by getByToken is different than that for getByLabel during an unscheduled call. This caused the DelayedGet signal to not be sent. The DelayedGet signal has now been moved to unscheduledFill since that is used by both call paths.
drop deprecated parameter enableDQMbyLumi
add a data member and public accessor for the path "exclusive" time
fill the DQM plots from internal buffers instead of on the fly
fix comments
use C++11 type aliases instead of public inheritance
migrate 'pre/postProcessPath' to 'pre/postPathEvent'
migrate 'pre/postProcessEvent' to 'pre/postEvent'
migrate 'preBeginRun' to 'preGlobalBeginRun', and 'pre/postModule' to 'pre/postModuleEvent'
drop 'prePathBeginRun', add 'preallocate', reorganise the plots

Cache the first/last path and endpath names by string instead of by
pointer; this makes the comparison slower, but we should migrate to
pathIDs anyway.
In the long term it's not clear whether it makes sense to keep track
of the "first" and "last" paths in a multithreaded environment.
work in progress