Merge pull request #2 from dvdheiden/patch-2

same button class option as the original jQuery dialog.

src/jquery.dialog.js

@@ -64,7 +64,7 @@ require:
         if (btnObj.constructor == Object) {
           id      = btnObj.id;
           text    = btnObj.text;
-          classed = btnObj.classed || classed;
+          classed = btnObj['class'] || btnObj.classed || classed;
           click   = btnObj.click;
         }