Add the "--show" and "--hide" cmdline parameters.

By default, turbostat shows all columns.

turbostat --hide counter_list
will continue showing all columns, except for those listed.

turbostat --show counter_list
will show _only_ the listed columns

These features work for built-in counters, and have no effect
on columns added with the --add parameter.
Signed-off-by: Len Brown <len.brown@intel.com>