- Upgraded target Android API level to 28 (Android 9)

- Moved some non-UI functionality from main activity to baresip service
- Simplified implementation of call transfer
- Modified baresip launcher and status bar images

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

@@ -1,6 +1,7 @@
 package com.tutpro.baresip
 
 import android.text.TextWatcher
+import android.util.Log
 import java.util.ArrayList
 
 class Call(val callp: String, val ua: UserAgent, val peerURI: String, val dir: String,
@@ -49,6 +50,5 @@ class Call(val callp: String, val ua: UserAgent, val peerURI: String, val dir: S
                 if (c.callp == callp) return c
             return null
         }
-
     }
 }