Setup kotlin project with gradle

I'm new to kotlin and gradle and tried to set up my very first project:

build.gradle

buildscript {
   ext.kotlin_version = '1.0.1-1'

   repositories {
     mavenCentral()
     jcenter()
   }

   dependencies {
     classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
   }
}

apply plugin: "kotlin"

src\main\kotlin\main.kt

package hello

fun main(args: Array<String>) {
   println("Hello World!")
}

And I get the error message "src\main\kotlin\main.kt: (4, 4): Unresolved reference: println".

The build.gradle file I copied from http://kotlinlang.org/docs/reference/using-gradle.html

I'd expect that the standard libraries are included automatically - or do I need to add something here?

I'm using gradle 2.12, JDK 1.8. (in case this matters)