Fix "background-color: primary_color" in generated css file

(issue ququplay#23)

Author: dryabov

src/stylus/functions/build_swatch.styl

@@ -116,7 +116,7 @@ build_swatch(swatch)
     .ui-bar-{swatch} .ui-checkbox-on:after,
     .ui-body-{swatch} .ui-checkbox-on:after,
     body .ui-group-theme-{swatch} .ui-checkbox-on:after,
-    .ui-btn.ui-checkbox-on.ui-btn-{swatch}:after,
+    .ui-btn.ui-checkbox-on.ui-btn-{swatch}:after
       background-color: primary_color
       border-color: primary_color
       color: font_color