Make "select *" work again
Add patch from Henrik Levkowetz to fix problem with returning multiple results
Make stdev return 0 instead of NaN when there are no rows
Add support for ordering on columns that aren't in the output (they
are included as hidden columns), move order by compilation to before
evaluation, this also makes the code easier to follow, fix some
potential problems with the tables array
Add -Wall, but disable a couple of specific warnings, fix the code
compile cleanly without warnings (mostly harmless stuff)