[ticket/377] Align portal columns right-to-left in rtl languages

With the old table layout, the left columns always displayed on the right
in rtl languages and vice-versa for the left right column. This should be
changed back in the tableless layout.

B3P-377

styles/prosilver/theme/portal.css

@@ -281,12 +281,20 @@ a.portal-forumtitle {
 	float: left;
 }
 
+.rtl #portal-left, .rtl #portal-right {
+	float: right;
+}
+
 #portal-center-wrapper {
 	width: 100%;
 	float: left;
 	display: block;
 }
 
+.rtl #portal-center-wrapper {
+	float: right;
+}
+
 #portal-column-area {
 	width: 100%;
 	margin: 0 auto;
@@ -296,6 +304,11 @@ a.portal-forumtitle {
 	margin-left: -100%;
 }
 
+.rtl #portal-left {
+	margin-right: -100%;
+	margin-left: 0;
+}
+
 /*
 * top spacing between portal body table and headerbar spacing is usually 10px
 */