gst/elements/: Added an element that writes to multiple filedescriptors at once.

gst/elements/: Added an element that writes to multiple filedescriptors at once.

Original commit message from CVS:
* gst/elements/Makefile.am:
* gst/elements/gstelements.c:
* gst/elements/gstmultifdsink.c: (gst_multifdsink_base_init),
(gst_multifdsink_class_init), (gst_multifdsink_init),
(gst_multifdsink_add), (gst_multifdsink_remove),
(gst_multifdsink_clear), (gst_multifdsink_chain),
(gst_multifdsink_set_property), (gst_multifdsink_get_property):
* gst/elements/gstmultifdsink.h:
Added an element that writes to multiple filedescriptors at once.