freetdm: Added new OOB event FTDM_OOB_POLARITY_REVERSE

Added new channel command FTDM_COMMAND_SET_POLARITY
         ftmod_wanpipe - Added support to enqueue polarity events on FXO lines
	 ftmod_wanpipe - Added support to set polarity on FXS lines
	 ftmod_analog - Added support to answer and hangup FXO lines on polarity reverse
	 ftmod_analog - Added support to reverse polarity in the FXS line on answer and hangup
	 mod_freetdm - Added parameters answer-on-polarity, hangup-on-polarity and polarity-delay
                       to enable those analog features

libs/freetdm/src/include/freetdm.h

@@ -557,8 +557,14 @@ typedef enum {
 	FTDM_COMMAND_COUNT,
 	FTDM_COMMAND_SET_RX_QUEUE_SIZE,
 	FTDM_COMMAND_SET_TX_QUEUE_SIZE,
+	FTDM_COMMAND_SET_POLARITY,
 } ftdm_command_t;
 
+typedef enum {
+	FTDM_POLARITY_FORWARD = 0,
+	FTDM_POLARITY_REVERSE = 1
+} ftdm_polarity_t;
+
 /*! \brief Custom memory handler hooks. Not recommended to use unless you need memory allocation customizations */
 typedef void *(*ftdm_malloc_func_t)(void *pool, ftdm_size_t len);
 typedef void *(*ftdm_calloc_func_t)(void *pool, ftdm_size_t elements, ftdm_size_t len);