Bookmarks: Code cosmetics

Spacing, namespaces, indirection, unused code...

Change-Id: Id2b0dccf7be0fc3b78305e16447f97546c6234bf
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/bookmarks/bookmarksplugin.cpp

@@ -52,13 +52,10 @@ using namespace Bookmarks::Constants;
 using namespace Bookmarks::Internal;
 using namespace TextEditor;
 
-BookmarksPlugin *BookmarksPlugin::m_instance = 0;
-
 BookmarksPlugin::BookmarksPlugin()
     : m_bookmarkManager(0),
       m_bookmarkMarginActionLineNumber(0)
 {
-    m_instance = this;
 }
 
 void BookmarksPlugin::extensionsInitialized()