title: error: package org.hamcrest does not exist Android Studio 1.5.1
body: <p>I am using Android studio 1.5.1.
  My build.gradle looks like below</p>
  
  <pre><code>allprojects {
          repositories {
              maven { url 'http://repo1.maven.org/maven2' }
          }
      }
  
      buildscript {
          repositories {
              jcenter()
          }
          dependencies {
              classpath 'com.android.tools.build:gradle:1.5.0'
          }
      }
      apply plugin: 'com.android.application'
  
      dependencies {
          // Unit testing dependencies
          testCompile 'org.hamcrest:hamcrest-library:1.3'
          testCompile 'junit:junit:4.12'
      }
  </code></pre>
  
  <p>I am writing some JUNIT test cases for my application as below</p>
  
  <pre><code>import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.is;
  
  public void testSomething throws Exception {
          ...
          assertThat(result, is(true));
  }
  </code></pre>
  
  <p>But when I am running the tests, it is showing that </p>
  
  <blockquote>
    <p>error: package org.hamcrest does not exist</p>
    
    <p>error: cannot find symbol assertThat(result, is(true));</p>
  </blockquote>
  
  <p>But I can go to the definition of assertThat, org.hamcrest etc from studio by going to definition as studio decompiles the jars. 
  Also I can see the package downloaded in .gradle/caches</p>
  
  <p>Can anyone suggest what I am doing wrong here?
  Normally Junit test cases using assertFalse, assertTrue etc is working, only hamcrest matching is giving errors.</p>