Absolute file path should be remembered for config path too.
Don't call g_main_current_source() if called directly.

If some function is called directly then g_main_current_source() will
return random value so this test is invalid, such usage should be
avoided and such function can be only callback, not directly called.
Fix: gtk_file_prop extension cannot be used stacked.

There is artefact that checks duplicates still around.
The commit removes it.
Implement LXShortcut using libfm-gtk file properties dialog.