[DotGNU]System compiles cleanly under csc

[Rhys Weatherley]

I've spent most of today getting the "System" assembly to
compile cleanly using MS'es compiler, which it now does.
No guarantee that it will work though.

I stubbed out things that were missing, added dummy return
values in empty methods, and generally cleaned up the errors.
I didn't really attempt to "fix" anything - there are lots of
TODO things in code that need attention.

I'm now working on System.Xml, plus a couple of cscc bugs
that have cropped up.  Hopefully I'll have the binaries for all
assemblies up in "pnet/samples" in the next day or two, so
we can bring the status page up to date.

The most common kinds of errors that I found were:

- Mispelled names.
- Too many parameters to "NotSupportedException".
- Using "x == 0" instead of "x == null" for object tests.
- String resources.
- Not using the "ref" and "out" keyword to pass parameters.

String resources was the big one, and contributors may
want to keep this one in mind.  The "_" method in "Object"
is not accessible to "System" and "System.Xml", so it
cannot be used to request resources.

I've created a private class in "System" called "S".
Use "S._" as the idiom to access resources in this
assembly instead of "_".  I'll be changing the XML
assembly to do the same shortly.

Cheers,

Rhys.