Add a method to clear all Profile's set properties

src/profile/Profile.h

@@ -445,6 +445,15 @@ public:
     /** Returns true if no properties have been set in this Profile instance. */
     bool isEmpty() const;
 
+    /**
+     * Clears all set properties in this profile. Afte calling this, isEmpty()
+     * will return true.
+     */
+    void clear()
+    {
+        _propertyValues.clear();
+    }
+
     /**
      * Returns true if this profile is the built-in profile.
      */