Add WebSocket functional tests

_From @muratg on Monday, January 4, 2016 2:32:28 PM_

_From @Tratcher on October 20, 2015 1:0_

_From @Sharpiro on October 19, 2015 17:29_

IHttpUpgradeFeature "IsUpgradableRequest" is never true in IIS Express profile, but works when running from kestrel via default "web" profile. Likely an issue with: `"Microsoft.AspNet.IISPlatformHandler": "1.0.0-beta8"`

Repro:

Create an empty web application from the asp.net 5 templates. Add the following lines of code inside `app.Run` inside Startup.cs:

```
var temp = context.Features.Get().IsUpgradableRequest;
var upgradeFeature = context.Features.Get();
```

Send the following line of code via a web browser:

```
var socket = new WebSocket("ws://localhost:---your port here---");
```

I am able to achieve a "true" value from "temp" when running from kestrel "web" profile only. The "temp" value is always false when running form IIS Express.

_Copied from original issue: aspnet/Home#1005_

_Copied from original issue: aspnet/IISIntegration#19_

_Copied from original issue: aspnet/WebSockets#67_

Start by reproducing the IHttpUpgradeFeature behavior described in Startup.cs with the IIS Express and Kestrel profiles, then inspect the existing functional-test structure. Done means adding WebSocket coverage that distinguishes the two hosting profiles and verifies the expected upgrade behavior.

Written by the indexing model from the issue text.