GUI -- Table headers can dynamically display with an icon which sorting direction the table is currently sorted as.

Change-Id: I6c5e6d1c196495dc6065ae58fa6cb21001c01778
diff --git a/web/gui/src/main/webapp/app/view/device/device.html b/web/gui/src/main/webapp/app/view/device/device.html
index aef1228..f8a62a0 100644
--- a/web/gui/src/main/webapp/app/view/device/device.html
+++ b/web/gui/src/main/webapp/app/view/device/device.html
@@ -4,6 +4,7 @@
     <table class="summary-list"
            onos-fixed-header
            ng-style="setTableHW()"
+           onos-sortable-header
            sort-callback="ctrl.sortCallback()">
         <thead>
             <tr>