move main project files into standard gradle/Android Studio layout

This makes it a lot easier to setup all the testing stuff.  Mostly,
I'm tired of fighting Android Studio's fragility, so I want to remove
as much non-standardness as possible in the hopes of improving that
situation.

closes #534 https://gitlab.com/fdroid/fdroidclient/issues/534

app/src/androidTest/java/mock/MockContextSwappableComponents.java

@@ -0,0 +1,43 @@
+package mock;
+
+import android.content.pm.PackageManager;
+import android.content.res.Resources;
+import android.test.mock.MockContentResolver;
+import android.test.mock.MockContext;
+
+public class MockContextSwappableComponents extends MockContext {
+
+    private PackageManager packageManager;
+    private Resources resources;
+    private MockContentResolver contentResolver;
+
+    public MockContextSwappableComponents setPackageManager(PackageManager pm) {
+        packageManager = pm;
+        return this;
+    }
+
+    public MockContextSwappableComponents setResources(Resources resources) {
+        this.resources = resources;
+        return this;
+    }
+
+    public MockContextSwappableComponents setContentResolver(MockContentResolver contentResolver) {
+        this.contentResolver = contentResolver;
+        return this;
+    }
+
+    @Override
+    public PackageManager getPackageManager() {
+        return packageManager;
+    }
+
+    @Override
+    public Resources getResources() {
+        return resources;
+    }
+
+    @Override
+    public MockContentResolver getContentResolver() {
+        return contentResolver;
+    }
+}