Make sure the colWidth array is correctly initialized in the ".explain"
command of the shell.
Additional test cases for skip-scan.
Fix some harmless compiler warnings in speedtest1.exe.
Fix spelling typo in speedtest1.exe.
Update documentation of sqlite3_column() for clarity.  Update evidence marks
on test cases.
Remove unnecessary local variables from sqlite3VdbeExec() in order to
reduce stack-space requirements of that routine.
Fix a test case in temptrigger.test so that it works in auto-vacuum mode.