Make compatible with F-Droid (#42)

* Make compatible with F-Droid
* Fix title bar empty

mobile/src/base/java/be/mygod/vpnhotspot/Timber.kt

@@ -0,0 +1,25 @@
+package be.mygod.vpnhotspot
+
+import android.util.Log
+import be.mygod.vpnhotspot.App.Companion.app
+import com.crashlytics.android.Crashlytics
+import io.fabric.sdk.android.Fabric
+import timber.log.Timber
+
+fun initTimber() {
+    Fabric.with(app, Crashlytics())
+    Timber.plant(object : Timber.Tree() {
+        override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
+            if (t == null) Crashlytics.log(priority, tag, message) else {
+                // Crashlytics.logException doesn't print to logcat
+                if (priority >= Log.WARN || priority == Log.DEBUG) Log.println(priority, tag, message)
+                if (priority >= Log.INFO) Crashlytics.logException(t)
+            }
+        }
+    })
+}
+
+fun debugLog(tag: String?, message: String?) {
+    if (BuildConfig.DEBUG) Timber.d(tag, message)
+    Crashlytics.log("$tag: $message")
+}