#422 menu_details for GTK UI

[Gergely Szasz]

This patch add menu details (similar to widget UI) ti GTK2/GTK3 UI.

• ui/gtk/gtkui.c, ui/ui.h:
  • new function: gtkui_update_menu_detail() to update one menu entry label
  • add menu_update_details() to menu_machine_select() to update menu labels when machine changes
• menu_data.pl:
  • new #include "ui/ui.h" to gtkui_update_menu_detail() declaration.
  • new mode in _dump_gtk : details - to generate menu_update_details() function
  • new generated function: menu_update_details() to update each menu item
  • add menu_update_details() to callbacks which has menu_detail
• menu.[hc]:
  • new menu_update_details() declaration
  • add menu_update_details() to appropriate MENU_CALLBACKs
• ui/gtk/gtkdisplay.c:
  • add menu_update_details() to drawing_area_resize() to update menu labels at startup and geometry changes (gfx filter changes)

[Gergely Szasz]

And here is a 'tooltip' version. It uses tooltips instead of changes menu item labels.

IMHO the first version is better.