fixes #9 - adds support for #load

Example use:

     //script1
            #load "script2.csx"
            using System;
            using System.Collections;

            Console.WriteLine("Hello Script 1");

     //script2
            using System;
            using System.Core;

            Console.WriteLine("Hello Script 2");

Will produce:

            using System;
            using System.Core;
            using System.Collections;

            Console.WriteLine("Hello Script 2");
            Console.WriteLine("Hello Script 1");

Also supports
 - being called inline (not just on top of the file).
 - absolute script paths (although am not sure about that)