Change the SQLITE_SCANSTAT_EST parameter so that it returns a double for
the estimated number of output rows per loop, rather than a 64-bit integer.
Revise the output format for the ".scanstats on" in the shell to make use
of this new capability.
Add the SQLITE_SCANSTAT_SELECTID metric.  Use it to improve the
".stmtscan on" output in the shell.
Changes the formatting of ".scanstats on" in the shell so that the stats for
subqueries are grouped together and occur after the main query.
On the ".scanstats on" output in the shell, initialize the estimated count for
the first loop of each subquery to the actual loop count.
Further improvements to the ".scanstats on" display in the shell.  Be sure
to show the results of all subqueries even if there are gaps in the 
SELECTID values.  Add ".scanstats" to the ".help" output.
Added SQLITE_SCANSTAT_SELECTID.  Change the value returned by
SQLITE_SCANSTAT_EST from sqlite3_int64 to double.  Enhanced the formatting
and display of scan statistics using the ".scanstats on" command in the
shell.
Update documentation on sqlite3_config() and add corresponding evidence marks.