Add streamProxy method to container handler

[sapessi]

• Framework version: 1.0
• Implementations: Jersey / Spring / Spring Boot / Spark

Add a new streamProxy(InputStream, OutputStream, Context) method to the LambdaContainerHandler object.

Scenario

Simplifies the task of writing Lambda RequestStreamHandler` classes from:

@Override
public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context)
			throws IOException {
	AwsProxyRequest request = LambdaContainerHandler.getObjectMapper().readValue(inputStream, AwsProxyRequest.class);
	AwsProxyResponse resp = handler.proxy(request, context);
	LambdaContainerHandler.getObjectMapper().writeValue(outputStream, resp);
        outputStream.close();
}

to:

@Override
public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context)
			throws IOException {
	handler.streamProxy(inputStream, outputStream, context);
}

[sapessi]

Added proxyStream method. Leaving this open until docs is updated.

[sapessi]

I've committed the updated docs in the next-release branch of the wiki. Closing this issue.