message: add two quick shortcuts
  add shortcut for bookmark manager and to refresh external devices
diff: @@ -219,6 +219,7 @@ void MainUI::setupIcons(){
  // Bookmarks menu
  ui->actionManage_Bookmarks->setIcon( LXDG::findIcon("bookmarks-organize","") );
  + ui->actionManage_Bookmarks->setShortcut(tr("CTRL+B"));
  ui->actionAdd_Bookmark->setIcon( LXDG::findIcon("bookmark-new","") );
  //GIT menu
  @@ -226,7 +227,8 @@ void MainUI::setupIcons(){
  ui->actionClone_Repository->setIcon( LXDG::findIcon("git","download") );
  // External Devices menu
  - ui->actionScan->setIcon( LXDG::findIcon("system-search","") );
  + ui->actionScan->setIcon( LXDG::findIcon("system-search","") )
  + ui->actionScan->setShortcut(tr("CTRL+E"));
  }
  //==========
  