gst/elements/gstfdsrc.*: Properly implement fdsrc. Removed signal and timeout, better implemented somewhere else.

Original commit message from CVS:
* gst/elements/gstfdsrc.c: (gst_fdsrc_class_init),
(gst_fdsrc_init), (gst_fdsrc_start), (gst_fdsrc_stop),
(gst_fdsrc_unlock), (gst_fdsrc_set_property),
(gst_fdsrc_get_property), (gst_fdsrc_create):
* gst/elements/gstfdsrc.h:
Properly implement fdsrc. Removed signal and timeout,
better implemented somewhere else.