Add Page::annotation

Will use it later

core/page.cpp

@@ -488,6 +488,16 @@ QLinkedList< Annotation* > Page::annotations() const
     return m_annotations;
 }
 
+Annotation * Page::annotation( const QString & uniqueName ) const
+{
+    foreach(Annotation *a, m_annotations)
+    {
+        if ( a->uniqueName() == uniqueName )
+            return a;
+    }
+    return nullptr;
+}
+
 const Action * Page::pageAction( PageAction action ) const
 {
     switch ( action )

core/page.h

@@ -249,6 +249,12 @@ class OKULARCORE_EXPORT Page
          */
         QLinkedList< Annotation* > annotations() const;
 
+        /**
+         * Returns the annotation with the given unique name.
+         * @since TODO
+         */
+        Annotation * annotation( const QString & uniqueName ) const;
+
         /**
          * Returns the @ref Action object which is associated with the given page @p action
          * or 0 if no page action is set.