Support hold/unhold in Zap, update IAX2 parser to know about modern commands, forward hold/unhold in dial, add hold device state

and implement holding in the SLA.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@37318 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/devicestate.h

@@ -43,6 +43,8 @@ extern "C" {
 #define AST_DEVICE_RINGING	6
 /*! Device is ringing *and* in use */
 #define AST_DEVICE_RINGINUSE	7
+/*! Device is on hold */
+#define AST_DEVICE_ONHOLD	8
 
 /*! \brief Devicestate watcher call back */
 typedef int (*ast_devstate_cb_type)(const char *dev, int state, void *data);

include/asterisk/pbx.h

@@ -52,6 +52,7 @@ enum ast_extension_states {
 	AST_EXTENSION_BUSY = 1 << 1,	/*!< All devices BUSY */
 	AST_EXTENSION_UNAVAILABLE = 1 << 2, /*!< All devices UNAVAILABLE/UNREGISTERED */
 	AST_EXTENSION_RINGING = 1 << 3,	/*!< All devices RINGING */
+	AST_EXTENSION_ONHOLD = 1 << 4,	/*!< All devices ONHOLD */
 };