initial changes to support siprec recording (#120)

* initial changes to support siprec recording

* include additional params on SIP INFO to start recording

* add support for maniupulating recording via REST API

* fixes from testing pause/resume recording

lib/utils/constants.json

@@ -120,6 +120,11 @@
     "verb:hook",
     "jambonz:error"
   ],
+  "RecordState": {
+    "RecordingOn": "recording_on",
+    "RecordingOff": "recording_off",
+    "RecordingPaused": "recording_paused"
+  },
   "MAX_SIMRINGS": 10,
   "BONG_TONE": "tone_stream://v=-7;%(100,0,941.0,1477.0);v=-7;>=2;+=.1;%(1400,0,350,440)",
   "FS_UUID_SET_NAME": "fsUUIDs"