* move helper-functions in navigationbar.cpp into NavigationBar [private]
* remove (unused) 2nd arg in WebSearchBar/NavigationBar and use mainClass as parent.
* remove NavigationBar-destructor (not needed)
* remove WebSearchBar::m_menu and create a QMenu-instance directly in WebSearchBar::contextMenuEvent()
- accessible in context menu on input
- added translations for plugins into resources so they can be loaded
- in access keys navigation plugin: lower case chars are choose first