add snd_device_name_hint() function and initial implementation

- add snd_device_name_hint() and snd_device_name_free_hint() functions
- add snd_ctl_iface_conf_name() functions
- do not accept parameters for the plugin definition without @args section
- add defaults.pcm.dmix.card/device and dsnoop.card/device definitions
- add hints for HDA-Intel.conf, pcm/dmix.conf, pcm/dsnoop.conf and alsa.conf
- add test/namehint test utility
- doxygen related cleanups

src/control/control.c

@@ -950,6 +950,7 @@ int snd_ctl_open_lconf(snd_ctl_t **ctlp, const char *name,
 #ifndef DOC_HIDDEN
 #define TYPE(v) [SND_CTL_ELEM_TYPE_##v] = #v
 #define IFACE(v) [SND_CTL_ELEM_IFACE_##v] = #v
+#define IFACE1(v, n) [SND_CTL_ELEM_IFACE_##v] = #n
 #define EVENT(v) [SND_CTL_EVENT_##v] = #v
 
 static const char *snd_ctl_elem_type_names[] = {
@@ -972,6 +973,16 @@ static const char *snd_ctl_elem_iface_names[] = {
 	IFACE(SEQUENCER),
 };
 
+static const char *snd_ctl_iface_conf_names[] = {
+	IFACE1(CARD, card),
+	IFACE1(HWDEP, hwdep),
+	IFACE1(MIXER, mixer),
+	IFACE1(PCM, pcm),
+	IFACE1(RAWMIDI, rawmidi),
+	IFACE1(TIMER, timer),
+	IFACE1(SEQUENCER, seq),
+};
+
 static const char *snd_ctl_event_type_names[] = {
 	EVENT(ELEM),
 };
@@ -999,6 +1010,17 @@ const char *snd_ctl_elem_iface_name(snd_ctl_elem_iface_t iface)
 	return snd_ctl_elem_iface_names[iface];
 }
 
+/**
+ * \brief get configuration name of related interface
+ * \param iface ala CTL interface identification
+ * \return ascii name of configuration interface
+ */
+const char *snd_ctl_iface_conf_name(snd_ctl_elem_iface_t iface)
+{
+	assert(iface <= SND_CTL_ELEM_IFACE_LAST);
+	return snd_ctl_iface_conf_names[iface];
+}
+
 /**
  * \brief get name of a CTL event type
  * \param type CTL event type