Update development guide

README.md

@@ -28,6 +28,11 @@ This version supports basic debugging capabilities.
 See http://aka.ms/vscclrdebugger for details.
 
 ### Development
+
+First install:
+* Node.js (newer than 4.3.1)
+* Npm (newer 2.14.12)
+
 To **run and develop** do the following:
 
 * Run `npm i`
@@ -35,7 +40,6 @@ To **run and develop** do the following:
 * *Optional:* run `tsc -w`, make code changes (on Windows, try `start node ".\node_modules\typescript\bin\tsc -w"`)
 * Press F5 to debug
 
-
 ## License  
 The Microsoft C# extension is subject to [these license terms](RuntimeLicenses/license.txt).  
 The source code to this extension is available on [https://github.com/OmniSharp/omnisharp-vscode](https://github.com/OmniSharp/omnisharp-vscode) and licensed under the [MIT license](LICENSE.txt).