- Allow the stats package user to determine in which mode to dump

-  Allow the stats package user to determine in which mode to dump
-  Factor out the formatted output into a display function
-  Make the stats package support tracing
-  Clean up output of binned data

base/statistics.cc:
    -  Factor out the formatted output into a display function and
    pass in the mode
    -  Make the stats package support tracing
    -  Clean up output of binned data
    -  Get rid of the list of binned stats and the map of bins
    since it is no longer needed for output
base/statistics.hh:
    -  Allow the stats package user to determine in which mode to dump

--HG--
extra : convert_revision : a1d5fc728f4dc22a851d58ea89d44018a94a64c7