Better readme.

README.md

@@ -1,22 +1,23 @@
-AsyncUnitTests
-==============
-
-Helpers for async unit testing.
+![logo](https://github.com/StephenCleary/AsyncUnitTests/raw/master/AsyncExUnitTests.128.png)
 
 Async-Aware Default Stub Behavior for Microsoft Fakes
-=====================================================
+===
 
 The built-in default stub behavior for Microsoft Fakes will return `null` tasks from asynchronous methods. The [Nito.AsyncEx.UnitTests.MSFakes NuGet package](https://www.nuget.org/packages/Nito.AsyncEx.UnitTests.MSFakes/) provides the `AsyncAwareDefaultValueStubBehavior` type.
 
 Recommended usage is to apply the async-aware default stub behavior to all unit tests in a project:
 
-    [AssemblyInitialize]
-    public static void Initialize(TestContext context)
-    {
-        StubBehaviors.Current = new Nito.Async.UnitTests.AsyncAwareDefaultValueStubBehavior();
-    }
+````C#
+[AssemblyInitialize]
+public static void Initialize(TestContext context)
+{
+  StubBehaviors.Current = new Nito.Async.UnitTests.AsyncAwareDefaultValueStubBehavior();
+}
+````
 
 However, it can be set on a test-by-test basis:
 
-    var stub = new Stub...;
-    stub.InstanceBehavior = new Nito.Async.UnitTests.AsyncAwareDefaultValueStubBehavior();
+````C#
+var stub = new Stub...;
+stub.InstanceBehavior = new Nito.Async.UnitTests.AsyncAwareDefaultValueStubBehavior();
+````