#load a .cs file without preprocessor or other hacking

[StingyJack]

This lets a .cs file be loaded and used as script. For me this solves some of the preprocessor directive hacking I was doing to reuse existing classes or get intellisense. (ideas gleaned from issue #36 )

There is a flowchart and some other docs that describe it more completely but the gist is that a derived SourceFileResolver is passed into the ScriptOptions, and it intercepts the calls to .cs files and uses SyntaxTree et.al. to provide a "namespace free" compiled version of the source that can be lifted into the script scope.

There are a few orphaned bits in the CsRewriter class that I left in because I think adding debugging support will require them.

I tried to not pollute this with the OutputBehavior PR. Please review and suggest any edits, corrections, or additions.

Example of the script with #load for .cs

#r ".\..\..\..\packages\NUnit.3.4.0\lib\net45\nunit.framework.dll"
#load "..\TestCs\ReferencedClass.cs"
#load "ReferencedScript.csx"

//Write using supplied ScriptContext
Output.WriteLine("namespace TestNamespace{class TestClass{public void TestMethod(){}}}");

//with the referenced assembly
var bag = new NUnit.Framework.Internal.PropertyBag();
Output.WriteLine($"// {bag}");

//With referenced script
Output.WriteLine($"// we have multiplied {Go4th(2, 3)}");

//Create instance from intercepted class
var rc1 = new ReferencedClass(Context);
Output.WriteLine($"// Emitting prop with backing field {rc1.PropertyWithBackingField}");
rc1.Owl($"// using the referenced class to output")

[daveaglick]

Yeah, the two files with this copyright header were copied wholesale from a Microsoft example.

[StingyJack]

Some of these classes are included in the newer VS shell references. You may be able to remove them if you up the shell ref's.

[daveaglick]

Good call - planning on continuing work on updating everything tomorrow so I'll take a look and see if they can be stripped.

[daveaglick]

Thanks. This pull request has been integrated manually.

[daveaglick]

Went ahead and merged this one, everything looks good. Unfortunately I'm having tons of other problems with the new Roslyn assemblies, so a release will have to wait a bit, but I'll get it out as soon as I can get everything working.