Options from the "Preferences" dialog added to the Search

Some code refactoring:
* use GUI_App::open_preferences() on all places where it's needed
* Preferences Dialog is an attribute of a ManeFrame class and created just ones during the MainFrame creation now.
* Created class Highlighter. Use it in Preferences and Tab

src/slic3r/GUI/MainFrame.hpp

@@ -32,6 +32,7 @@ class Tab;
 class PrintHostQueueDialog;
 class Plater;
 class MainFrame;
+class PreferencesDialog;
 
 enum QuickSlice
 {
@@ -203,6 +204,7 @@ public:
     DiffPresetDialog      diff_dialog;
     wxWindow*             m_plater_page{ nullptr };
 //    wxProgressDialog*     m_progress_dialog { nullptr };
+    PreferencesDialog*    preferences_dialog { nullptr };
     PrintHostQueueDialog* m_printhost_queue_dlg;
 //    std::shared_ptr<ProgressStatusBar>  m_statusbar;