ARI: Add tones playback resource

Adds a tones URI type to the playback resource. The tone can be specified by
name (from indications.conf) or by a tone pattern. In addition, tonezone can
be specified in the URI (by appending ;tonezone=<zone>). Tones must be
stopped manually in order for a stasis control to move on from playback of
the tone. Tones may be paused, resumed, restarted, and stopped. They may
not be rewound or fast forwarded (tones can't be controlled in a way that
lets you skip around from note to note and pausing and resuming will also
restart the tone from the beginning). Tests are currently in development
for this feature (https://reviewboard.asterisk.org/r/3428/).

(closes issue ASTERISK-23433)
Reported by: Matt Jordan
Review: https://reviewboard.asterisk.org/r/3427/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@412535 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/app.h

@@ -879,6 +879,14 @@ int ast_control_streamfile_lang(struct ast_channel *chan, const char *file,
 	const char *fwd, const char *rev, const char *stop, const char *suspend,
 	const char *restart, int skipms, const char *lang, long *offsetms);
 
+/*!
+ * \brief Controls playback of a tone
+ *
+ * \retval 0 on success
+ * \retval Non-zero on failure
+ */
+int ast_control_tone(struct ast_channel *chan, const char *tone);
+
 /*!
  * \brief Stream a file with fast forward, pause, reverse, restart.
  * \param chan