Adding clear button to pathpainter

Change-Id: I9fbd2f9e5483e5567156f814cd5e03fced711b78

@@ -47,7 +47,7 @@
 
     function clear() {
         wss.sendEvent(clearMessage);
-        flash.flash('Source node: ' + node.id);
+        flash.flash('Cleared source and destination');
     }
 
     function setSrc(node) {
@@ -79,7 +79,6 @@
         wss.sendEvent(prevPathMessage);
     }
 
-
     function setMode(mode) {
         if (currentMode === mode) {
             $log.debug('(in mode', mode, 'already)');

@@ -210,9 +210,16 @@
                 tt: 'Highlight next path',
                 gid: 'nextIntent'
             },
+            0: {
+                cb: function () {
+                    pps.clear();
+                },
+                tt: 'Clear source and destination',
+                gid: 'xMark'
+            },
 
             _keyOrder: [
-                'openBracket', 'closeBracket', '3', '4', '5', '6', 'leftArrow', 'rightArrow'
+                'openBracket', 'closeBracket', '3', '4', '5', '6', 'leftArrow', 'rightArrow', '0'
             ]
         },