- support for global flags persistence

- support for fifo dump_gflags command
- support for fifo flush_gflags command
- flush_gflags script command added

usr_avp.h

@@ -62,6 +62,7 @@
 #define AVP_FR_TIMER     "fr_timer"      /* Value of final response timer */
 #define AVP_FR_INV_TIMER "fr_inv_timer"  /* Value of final response invite timer */
 #define AVP_RPID         "rpid"          /* Remote-Party-ID */
+#define AVP_GFLAGS        "gflags"       /* global flags */
 
 
 struct str_int_data {