Add test for issue #66.

tests/issue-66-yield-eventloop-exit.d

@@ -0,0 +1,19 @@
+/+ dub.sdl:
+	name "tests"
+	dependency "vibe-core" path=".."
++/
+module tests;
+
+import vibe.core.core;
+
+void main()
+{
+	bool visited = false;
+	runTask({
+		yield();
+		visited = true;
+		exitEventLoop();
+	});
+	runApplication();
+	assert(visited);
+}