title: kotlin project can't be build in gradle
body: <p>I have a java project that write in kotlin ,i use intelliJ IDEA to develop this project.  I have trouble on the dependencies setting (multiple project). I already read lot of examples , but I can't find the workaround , here is my dependencies setting code,
  it can be build in java class correctly , but the kotlin class will get lot of error 'Unresolved reference' . Is that any wrong about my setting or gradle is not suitable with kotlin . </p>
  
  <p>PS : when i only build core project , build process will successful , but build at test project will get the reference unresolved error   </p>
  
  <pre><code>allprojects {
  apply plugin: 'java'
  apply plugin: 'kotlin'
  group 'testProject'
  version '1.0'
  }
  
  
  
  subprojects{
  apply plugin:  'java'
  apply plugin: 'kotlin'
  def defaultEncoding = 'UTF-8'
  compileJava.options.encoding = defaultEncoding
  sourceCompatibility = 1.8
  targetCompatibility = 1.8
  
  repositories {
      mavenCentral()
      mavenLocal()
  }
  
  dependencies {
  
      // Kotlin
      compile "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
      compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
      compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
  }
  }
  project(':test') {
  dependencies {
      compile project(':core')
      compile project(':testTwo')
  }
  
  project(':testTwo'){
  dependencies{
      compile project(':core')
  }
  </code></pre>
  
  <p>setting.gradle</p>
  
  <pre><code>include 'test','testTwo','core'
  </code></pre>