build.gradle: get the instrument tests building

android/build.gradle

 
 apply plugin: 'android'
 
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    instrumentTestCompile 'org.hamcrest:hamcrest-all:1.3'
+}
+
 android {
     buildToolsVersion '18.0'
     compileSdkVersion 18
             java.srcDirs = ['src']
             res.srcDirs = ['res']
         }
+        instrumentTest.setRoot('eSpeakTests')
+        instrumentTest {
+            java.srcDirs = ['eSpeakTests/src']
+        }
     }
 }