yoda: Rename _validate into _fixup_choices

There will be a little bit more post-options-parse actions, so
prepare for it.

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>
yoda: Add args parsing

It should be quite simple. The getopt_long moves all the unrecognized
argv-s to the end of this array and all we need is to just pick them
up there. Some more work with optional arguments (those with default
string in .yoda file) should still be done though.

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