[DotGNU]Xsharp and improved PInvoke support

[Rhys Weatherley]

I've been fixing a bunch of bugs in the compiler and engine
that should help make PInvoke call-outs smoother.

In particular, I found a nasty bug in the assembler/linker
that caused it to completely mess up the order of structs
with sequential or explicit layout.  This is fixed now.

I just uploaded a new version of Xsharp, which uses these
facilities.  I've got simple paint event handling working now,
which is very cool.  It's still not usable as a full-blown
GUI abstraction layer, but it's getting there.

http://www.southern-storm.com.au/download/xsharp.tar.gz

You will need the latest CVS version of pnet to build this.

Cheers,

Rhys.