New Feature: Add initialization scripts in Script Pack

Add a collection of scripts into a Script Pack allowing you to define functions and more.

Allows you to do something like this in your script pack:

void IScriptPack.Initialize(IScriptPackSession session)
{
    session.AddInitializationScripts(
        new string[] {
            "Action<string> ls = (filespec)=>{ foreach (var f in new System.IO.DirectoryInfo(\".\").GetFiles(filespec)) { Console.WriteLine(f);} };"
        }
    );
}

While allows you to do something like this in REPL:

ls("*.dll");