Specify AndroidManifest.xml location to run tests in IDE.

The location of the AndroidManifest.xml file now has to be specified to run in Intellij otherwise you get the following error:

WARNING: No manifest file found at /Users/me/work/deckard-gradle/AndroidManifest.xml.Falling back to the Android OS resources only.
To remove this warning, annotate your test class with @Config(manifest=Config.NONE).
WARNING: no system properties value for ro.build.date.utc
DEBUG: Loading resources for android from jar:/Users/me/.m2/repository/org/robolectric/android-all/4.1.2_r1-robolectric-0/android-all-4.1.2_r1-robolectric-0.jar!/res...

android.content.res.Resources$NotFoundException: unknown resource 2130837504
	at org.robolectric.shadows.ShadowAssetManager.getAndResolve(ShadowAssetManager.java:272)
	at org.robolectric.shadows.ShadowAssetManager.getResourceValue(ShadowAssetManager.java:85)
	at android.content.res.AssetManager.getResourceValue(AssetManager.java)
	at android.content.res.Resources.getValue(Resources.java:1009)
	at android.content.res.Resources.loadXmlResourceParser(Resources.java:2098)
	at android.content.res.Resources.getLayout(Resources.java:852)
	at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
	at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
	at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:256)
	at android.app.Activity.setContentView(Activity.java:1867)
	at com.example.robolectric.DeckardActivity.onCreate(DeckardActivity.java:12)
	at android.app.Activity.performCreate(Activity.java:5008)
	at org.fest.reflect.method.Invoker.invoke(Invoker.java:112)
	at org.robolectric.util.ActivityController$1.run(ActivityController.java:147)
	at org.robolectric.shadows.ShadowLooper.runPaused(ShadowLooper.java:265)
	at org.robolectric.util.ActivityController.create(ActivityController.java:144)
	at org.robolectric.util.ActivityController.create(ActivityController.java:154)
	at com.example.activity.DeckardActivityRobolectricTest.testSomething(DeckardActivityRobolectricTest.java:18)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:250)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:177)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)