Fixes & early adoptation to AS 4.0

build.gradle

@@ -1,15 +1,15 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.3.60'
     ext.nav_version = '2.2.0-beta01'
 
     repositories {
         google()
         jcenter()
-
+        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.1'
+        classpath 'com.android.tools.build:gradle:4.0.0-alpha03'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath "org.jetbrains.dokka:dokka-android-gradle-plugin:0.9.18"
         classpath "de.mannodermaus.gradle.plugins:android-junit5:1.5.1.0"
@@ -29,14 +29,10 @@ allprojects {
     repositories {
         google()
         jcenter()
-
+        maven { url 'https://dl.bintray.com/kotlin/kotlin-eap' }
     }
 }
 
-task clean(type: Delete) {
-    delete rootProject.buildDir
-}
-
 task removeReports(type: Delete) {
     delete fileTree(rootProject.projectDir.path + "/reports") {
         include '**/*.*'