yoda: Remove duplicate groups when classifying opts

One option can be added into several groups twice when
it depends on other options. Fix that.

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>
yoda: Allow for custom names in 'hgroup' string

And fix for help text generation for this case.

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>