Make compatible with F-Droid (#42)

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

mobile/build.gradle

@@ -1,8 +1,10 @@
 apply plugin: 'com.android.application'
-apply plugin: 'io.fabric'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-kapt'
 
+if (getGradle().getStartParameter().getTaskRequests().toString().contains("base"))
+    apply plugin: 'io.fabric'
+
 android {
     buildToolsVersion "28.0.3"
     compileSdkVersion 28
@@ -31,8 +33,15 @@ android {
         }
     }
     dataBinding.enabled = true
-    flavorDimensions("freedom")
+    flavorDimensions("fdroid", "freedom")
     productFlavors {
+        base {
+            dimension "fdroid"
+        }
+        fdroid {
+            dimension "fdroid"
+        }
+
         freedom {
             dimension "freedom"
             buildConfigField "boolean", "DONATIONS", "true"
@@ -52,18 +61,20 @@ dependencies {
     implementation "androidx.core:core-ktx:$androidxVersion"
     implementation "androidx.preference:preference:$androidxVersion"
     implementation "androidx.room:room-runtime:$roomVersion"
-    implementation 'com.android.billingclient:billing:1.1'
-    implementation 'com.crashlytics.sdk.android:crashlytics:2.9.5'
     implementation 'com.github.luongvo:BadgeView:1.1.5'
     implementation 'com.github.topjohnwu:libsu:2.0.2'
     implementation "com.google.android.material:material:$androidxVersion"
+    implementation 'com.jakewharton.timber:timber:4.7.1'
     implementation 'com.linkedin.dexmaker:dexmaker-mockito:2.19.1'
     implementation 'com.takisoft.preferencex:preferencex:1.0.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"
+    baseImplementation 'com.android.billingclient:billing:1.1'
+    baseImplementation 'com.crashlytics.sdk.android:crashlytics:2.9.5'
     testImplementation "androidx.room:room-testing:$roomVersion"
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test:runner:1.1.0-alpha4'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha4'
 }
 
-apply plugin: 'com.google.gms.google-services'
+if (getGradle().getStartParameter().getTaskRequests().toString().contains("base"))
+    apply plugin: 'com.google.gms.google-services'