Ported the gstfilter plugin to GStreamer 0.10.

Ported the gstfilter plugin to GStreamer 0.10.

Original commit message from CVS:
Patch by: Mathis Hofer <mathis dot hofer at dreamlab dot net>
* configure.ac:
* gst/filter/Makefile.am:
* gst/filter/gstbpwsinc.c: (gst_bpwsinc_dispose),
(gst_bpwsinc_base_init), (gst_bpwsinc_class_init),
(gst_bpwsinc_init), (bpwsinc_set_caps), (bpwsinc_transform_ip),
(bpwsinc_set_property), (bpwsinc_get_property):
* gst/filter/gstfilter.c: (plugin_init):
* gst/filter/gstfilter.h:
* gst/filter/gstiir.c: (gst_iir_dispose), (gst_iir_base_init),
(gst_iir_class_init), (gst_iir_init), (iir_set_caps),
(iir_transform_ip), (iir_set_property), (iir_get_property):
* gst/filter/gstlpwsinc.c: (gst_lpwsinc_dispose),
(gst_lpwsinc_base_init), (gst_lpwsinc_class_init),
(gst_lpwsinc_init), (lpwsinc_set_caps), (lpwsinc_transform_ip),
(lpwsinc_set_property), (lpwsinc_get_property):
Ported the gstfilter plugin to GStreamer 0.10.