[css2] Added "level" field to the sample property.

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%401951

Author: bert-github

css2/properties/sample.db

@@ -4,5 +4,6 @@
    elements this property applies to;;
    whether the property is inherited;;
    how percentage values are interpreted;;
-   which media groups the property applies to
+   which media groups the property applies to;;
+   2 2.1
 */