Add the GLIB_AVAILABLE_IN_ALL annotation to all old functions (that
haven't already been annotated with the GLIB_AVAILABLE_IN_* macros or a
deprecation macro).
If we discover in the future that we cannot use only one macro on
Windows, it will be an easy sed patch to fix that.
https://bugzilla.gnome.org/show_bug.cgi?id=688681
This implements all the GIOStream file ops for local files.
We use the "fallback to output stream" for all GFileIOStream ops.
Some helpers stuff was added to the local input and output streams
so they could be reused.
