Upgrade project to Azure Functions v2 RTM

[dchristensen]

As part of the upgrade, a developer's local machine should include a file called local.settings.json the project root with the following content:

{
  "IsEncrypted": false,
  "Values": {
    "FUNCTIONS_EXTENSION_VERSION ": "~2",
    "FUNCTIONS_WORKER_RUNTIME":  "dotnet", 
    "AzureWebJobsStorage": "UseDevelopmentStorage=true"
  }
}