* map exception names to HTTP Status Code (Forbidden => 403, Unauthorized => 401, etc...)
* review toString on Value API (removal of QueryStringValue?)
* tests and coverage

Jetty close exception:
MvcTest#mvcDispatch
```
GET /method 500 Server Error
java.io.IOException: Close org.eclipse.jetty.server.HttpConnection$SendCallback@1f1eae2a[PROCESSING][i=HTTP/1.1{s=200,h=3,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$SendCallback@11d953b9] in state PROCESSING
	at org.eclipse.jetty.util.IteratingCallback.close(IteratingCallback.java:428)
	at org.eclipse.jetty.server.HttpConnection.onClose(HttpConnection.java:510)
	at org.eclipse.jetty.io.SelectorManager.connectionClosed(SelectorManager.java:345)
	at org.eclipse.jetty.io.ManagedSelector$DestroyEndPoint.run(ManagedSelector.java:967)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
	at java.lang.Thread.run(Thread.java:748)
```

FeaturedKotlinTest.coroutineNoSuspend:
async:

```
	Suppressed: java.io.IOException: Close org.eclipse.jetty.server.HttpConnection$SendCallback@4b406dd7[PROCESSING][i=HTTP/1.1{s=200,h=3,cl=-1},cb=org.eclipse.jetty.server.HttpChannel$SendCallback@e42eadb] in state PROCESSING
		at org.eclipse.jetty.util.IteratingCallback.close(IteratingCallback.java:428)
		at org.eclipse.jetty.server.HttpConnection.onClose(HttpConnection.java:510)
		at org.eclipse.jetty.io.SelectorManager.connectionClosed(SelectorManager.java:345)
		at org.eclipse.jetty.io.ManagedSelector$DestroyEndPoint.run(ManagedSelector.java:967)
		... 3 more
```