gst/equalizer/: Add 3 and 10 band version and add missing gst_object_sync_values.

gst/equalizer/: Add 3 and 10 band version and add missing gst_object_sync_values.

Original commit message from CVS:
* gst/equalizer/Makefile.am:
* gst/equalizer/gstiirequalizer.c: (_do_init),
(gst_iir_equalizer_band_set_property),
(gst_iir_equalizer_band_class_init),
(gst_iir_equalizer_band_get_type),
(gst_iir_equalizer_child_proxy_get_child_by_index),
(gst_iir_equalizer_child_proxy_get_children_count),
(gst_iir_equalizer_child_proxy_interface_init), (setup_filter),
(gst_iir_equalizer_compute_frequencies),
(gst_iir_equalizer_transform_ip), (plugin_init):
* gst/equalizer/gstiirequalizer10bands.c:
(gst_iir_equalizer_10bands_base_init),
(gst_iir_equalizer_10bands_class_init),
(gst_iir_equalizer_10bands_init),
(gst_iir_equalizer_10bands_set_property),
(gst_iir_equalizer_10bands_get_property):
* gst/equalizer/gstiirequalizer10bands.h:
* gst/equalizer/gstiirequalizer3bands.c:
(gst_iir_equalizer_3bands_base_init),
(gst_iir_equalizer_3bands_class_init),
(gst_iir_equalizer_3bands_init),
(gst_iir_equalizer_3bands_set_property),
(gst_iir_equalizer_3bands_get_property):
* gst/equalizer/gstiirequalizer3bands.h:
* gst/equalizer/gstiirequalizernbands.c:
(gst_iir_equalizer_nbands_base_init),
(gst_iir_equalizer_nbands_init):
Add 3 and 10 band version and add missing gst_object_sync_values.
* gst/spectrum/gstspectrum.c: (gst_spectrum_event),
(gst_spectrum_transform_ip):
Add some comments about float support.