[Frontend] Styling Export button

fixes #973
- In progress:
- Added new download symbol to symbols font;
- Added export symbol to export button;
- Layout/markup/SASS for historical tabular
view modified;

platform/commonUI/general/res/sass/lists/_tabular.scss

@@ -162,4 +162,14 @@ table {
 			min-width: 150px;
 		}
 	}
+}
+
+/********************************************************** SPECIFIC TABULAR VIEWS */
+.t-tabular {
+    &.t-historical {
+        $btnExportH: 25px;
+        .l-view-section {
+            top: $btnExportH + $interiorMargin;
+        }
+    }
 }