Add the experimental sqlite3_stmt_scanstatus() API.
Minor fixes and documentation improvements for sqlite3_stmt_scanstatus().
If SQLITE_ENABLE_STMT_SCANSTATUS is defined, record the number of times each VDBE opcode is executed. Derive the values returned by sqlite3_stmt_scanstatus() from these records on demand.
Minor performance enhancements to SQLITE_ENABLE_STMT_SCANSTATUS code.
Remove unused variable from struct WhereInfo. Add some explanatory comments to new code.
Add further tests. Fixes so that compilation without ENABLE_STMT_SCANSTATUS works.
Refactor the interface to make it more easily extensible.
Fix a typo preventing this from building with SQLITE_ENABLE_STMT_SCANSTATUS defined.
Add the experimental sqlite3_stmt_scanstatus() API. For comparing the number of rows actually visited by a loop with the estimate used by the query planner.
Updates to the sqlite3_stmt_scanstatus() documentation.  No changes to code.