Add integration test for FeedManager

Attention: This factors out a DnsModule to be able to make actual
non-Tor DNS lookups for testing.

bramble-core/src/test/java/org/briarproject/bramble/test/TestSocksModule.java

@@ -0,0 +1,16 @@
+package org.briarproject.bramble.test;
+
+import javax.net.SocketFactory;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class TestSocksModule {
+
+	@Provides
+	SocketFactory provideSocketFactory() {
+		return SocketFactory.getDefault();
+	}
+
+}