Listview: increase level of specificity of the margin 0 rule for list…

…view buttons to avoid margins when used in grid. Fixes #4945

css/structure/jquery.mobile.listview.css

@@ -6,6 +6,7 @@ ol.ui-listview, ol.ui-listview .ui-li-divider { counter-reset: listnumbering; }
 .ui-collapsible-content .ui-listview-inset { margin: .5em 0; }
 .ui-listview, .ui-li { list-style:none; padding:0; }
 .ui-li, .ui-li.ui-field-contain { display: block; margin:0; position: relative; overflow: visible; text-align: left; border-width: 0; border-top-width: 1px; }
+.ui-li.ui-btn { margin: 0; }
 .ui-li .ui-btn-text a.ui-link-inherit { text-overflow: ellipsis; overflow: hidden; white-space: nowrap; }
 .ui-li-static { background-image: none; }
 .ui-li-divider { padding: .5em 15px; font-size: 14px; font-weight: bold; }