Added usage examples

* Cleaned up project.json

* Updated README with example on how to deserialize json request body

* Added reference to System.Runtime.Serialization.Json as this would seems a common usage

* Added C# example files to the /Examples directory

examples/dotnet/arguments.cs

@@ -0,0 +1,11 @@
+using System;
+using Fission.DotNetCore.Api;
+
+public class FissionFunction 
+{
+    public string Execute(FissionContext context){
+        var x = Convert.ToInt32(context.Arguments["x"]);
+        var y = Convert.ToInt32(context.Arguments["y"]);
+        return (x+y).ToString();
+    }
+