[Vala] missing FileStream flush

["Stefan Zimmermann" <s zimmermann stud fh-sm de>]

hello,

i hope this is the right place for such messages...

i found a little missing feature in the GLib.FileStream class.
i had to manually flush a FileStream but there was no definition of a
flush method in the FileStream definition.
so i added the method 'flush ()' with reference to the fflush function
from stdio to the FileStream section of the glib vapi and it works fine.

maybe this should generally be added to the glib vapi...
or maybe there is already another way to flush a FileStream. i don't know...
;-)