Add Windows Server Monitor to NuGet package.

This commit is for issue #4 which adds the New Relic Windows Server Monitor to the NuGet package for Azure cloud services. I performed a  simple test with the default ASP.NET MVC 5 project with a Azure web role in Visual Studio 2013. 

### Remaining Work
- [x] Add the Windows Server Monitor (WSM) MSI.
- [ ] Add check for .NET 4 when installing WSM.
- [x] ~~Make WSM optional.~~ _It will remain as is. If a user wishes to turn off the Server Monitor install, they can comment out the relevant line in_ `newrelic.cmd`.
- [x] Add necessary tests. _No additional tests are necessary._

### Questions 
- Is the check for .NET 4 required? When I run it with the Azure 2.2 SDK it installs just fine. But I'm not sure when it comes to older versions.
- Do you want me to include any additional tests? I noticed that there aren't any tests that verify changes to web.config or the service definition file so I wasn't sure if you want me to try to tackle that.
- How would you like this to be optional? Personally I like having the Server Monitor installed on every role that I'm monitoring since there is no extra charge for server monitoring. If that changes then of course having it optional is needed. One idea is to have an additional dialog asking the user if they want to include the Server Monitor with Yes/No buttons.