- fixed callee completion from contacts

- moved restoring of call and message history from baresip service to
  main activity
- small cleanups

app/src/main/kotlin/com/tutpro/baresip/Api.kt

@@ -5,5 +5,7 @@ object Api {
     external fun audio_codecs(): String
     external fun call_peeruri(callp: String): String
     external fun cmd_exec(cmd: String): Int
+    external fun contact_add(contact: String)
+    external fun contacts_remove()
 
 }