upgrade to gradle 4.1

android/build.gradle

@@ -1,5 +1,5 @@
 android {
-    buildToolsVersion "23.0.1"
+    buildToolsVersion "26.0.2"
     compileSdkVersion 20
     sourceSets {
         main {

build.gradle

@@ -6,9 +6,10 @@ buildscript {
         mavenCentral()
         maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.0'
+        classpath 'com.android.tools.build:gradle:3.0.1'
         
 
     }
@@ -75,6 +76,19 @@ project(":core") {
     }
 }
 
+subprojects {
+    if(it.name != "android") { // android plugin is not compatible with java plugin
+        apply plugin: "java"
+        apply plugin: "idea"
+        idea {
+            module {
+                scopes.PROVIDED.minus += [configurations.compile]
+                scopes.COMPILE.plus += [configurations.compile]
+            }
+        }
+    }
+}
+
 tasks.eclipse.doLast {
     delete ".project"
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Jun 09 23:06:52 EDT 2017
+#Sat Nov 25 13:49:47 CET 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip