FE/Qt: Precompiled header hacking (work in progress).
FE/Qt: file header cleanups.
FE/Qt4: make .desktop files executable
FE/Qt4: reverted r68647
FE/Qt4: change the vbox icon name
FE/Qt4: Remove no display, cause it prevent the display of the shortcut with some window managers.
FE/Qt4-x11: little update
FE/Qt4: Move platform specific code to platform/. Start to harmonize classes for the different platforms with have. Add UIDesktopServices for handling desktop specific tasks.