[mythtv] underscan OSD only

[Jim Paris]

> The OSD overscan settings are completely separate from the GUI positioning 
> settings -- they're always relative to the decoded video size (not the 
> display size).  Not really sure what the issue is, here =)

OK maybe I'm just being stupid and belong on the -users list then.
But which "OSD overscan settings" are you referring to?  If I set
HorizScanPercentage and VertScanPercentage to, say, -10, then my video
displays 10% smaller.  I don't want that.  I want the video to still
display fullscreen with no scaling, and just the OSD overlay to
display 10% smaller.  I haven't found a combination of settings that
does this, which is why I proposed adding the option. :)

-jim