Created Issue: Resurrecting the XSDs for Intellisense [11579]

I'm creating this as an issue because, as fast as I can tell, I can't attach a file to a discussion.
See the original discussion [here](http://msbuildextensionpack.codeplex.com/discussions/433016).

I wrote some magic to automatically generate a corresponding .xsd when the 'Framework' (the project for the main MSBuild.ExtensionPack.dll) is built, for the Main3.5 subtree.

Attached is the patch that makes it happen. If you like it, I'll adapt it for all the other projects, in both 3.5 and 4.0.