ext/pulse/: Use GST_BOILERPLATE everywhere and fix coding style at some places.

ext/pulse/: Use GST_BOILERPLATE everywhere and fix coding style at some places.

Original commit message from CVS:
* ext/pulse/pulsemixer.c: (gst_pulsemixer_class_init),
(gst_pulsemixer_set_property), (gst_pulsemixer_get_property):
* ext/pulse/pulsemixerctrl.c: (gst_pulsemixer_ctrl_subscribe_cb),
(gst_pulsemixer_ctrl_open), (gst_pulsemixer_ctrl_timeout_event),
(gst_pulsemixer_ctrl_set_volume):
* ext/pulse/pulsemixertrack.c: (gst_pulsemixer_track_new):
* ext/pulse/pulseprobe.c: (gst_pulseprobe_open):
* ext/pulse/pulsesink.c: (gst_pulsesink_class_init),
(gst_pulsesink_init), (gst_pulsesink_open),
(gst_pulsesink_prepare), (gst_pulsesink_write),
(gst_pulsesink_delay), (gst_pulsesink_reset):
* ext/pulse/pulsesrc.c: (gst_pulsesrc_class_init),
(gst_pulsesrc_init):
Use GST_BOILERPLATE everywhere and fix coding style at some places.
Fix a locking issue in pulsesink's prepare function.
* ext/pulse/pulseutil.c: (gst_pulse_channel_map_to_gst):
Check if the created channel layout is valid for GStreamer.