Added readstats and writestats features which allow for saves and reuse of

profile stats between runs of the requestprofiler.

Added urlfocus mode.  Urlfocus mode presents a summary of activity
within a period of time before and after the invocation of a particular
URL as it was recorded in the big M log.  This can be useful when trying
to track down a problem which you believe is related to some series
of URL invocations as opposed to a single URL invocation.

Fixed bug in timed mode which effected average stats.