Original commit message from CVS:
* gst/spectrum/Makefile.am:
Link to base libraries
* gst/spectrum/demo-osssrc.c: (main):
use new threshhold property
* gst/spectrum/gstspectrum.c: (gst_spectrum_class_init),
(gst_spectrum_init), (gst_spectrum_dispose),
(gst_spectrum_set_property), (gst_spectrum_set_sink_caps),
(gst_spectrum_get_sink_caps), (gst_spectrum_chain),
(gst_spectrum_change_state):
* gst/spectrum/gstspectrum.h:
Use gst_adapter, support multiple-channels, add threshold property for
result, add docs, fix resulting spectrum range (was including mirrored
results)