Rename README.md to problem 4

homework-1-C--march-2014
========================
/*Problem 4.Hello World
Create, compile and run a “Hello C#” console application. 
Ensure you have named the application well (e.g. “”HelloCSharp”). 
You should submit the Visual Studio project holding the HelloCSharp class as part of your homework.*/

using System;
class HelloCSharp
{
    static void Main()
    {
        Console.WriteLine("HelloCSharp");
    }
}