Properly clear EditorStatus.message with empty()

Partially resolves processing#1167 - EditorStatus.message no longer gets set to a
string of spaces when cleared, which caused some UI bugs.

Author: aj-m

app/src/processing/app/ui/Editor.java

@@ -2665,7 +2665,7 @@ public int getStatusMode() {
    * Clear the status area.
    */
   public void statusEmpty() {
-    statusNotice(EMPTY);
+    status.empty();
   }