There’s fat country music, which celebrates the callused pleasures of hard work, and there’s lean country music, which is the sound of having no work at all.  Kentucky singer-songwriter Chris Knight’s third LP is lean but sturdy: There’s vitality and brawn behind his weather-beaten voice.  Knight’s songs are peopled with folks who drive hundreds of miles for uncertain love, who rob liquor stores for kicks, whose abusive husbands mysteriously disappear -- and he always lets us under their skin.  Even the arrangements have a stone-soup simplicity.  The supple beauty of a lap-steel guitar line might jump out every now and then, but spare in Knight’s world, economy is a virtue.  It doesn’t matter whether you’re talking about love or money -- there’s never a scrap to waste