Release validator for NH 4.0

Updated projects to .NET 4.0 and NHibernate 4.0.1
Projects are signed using reference to shared license file
Using NuGet packages whenever possible (except SharpTextEx)
Removed non-generic-collection-related members from unit tests
Updated release notes
Updated build scripts for .NET 4.0 and appropriate locations of assemblies
Commented out sign attribute in common assembly info

Thanks, will do.

Validator is already forked into the NHibernate organization at Github (https://github.com/nhibernate/NHibernate-Validator). This one already has more commits than darioquintana/NHibernate-Validator has.

The PRs should probably be resubmitted against the nhibernate/NHibernate-Validator fork.

@Dario Quintana, @Dario Quintana, @Alex Zaytsev, @Oskar Berggren: Hi, are we going to bring this together with NHibernate core?

Pull request for https://nhibernate.jira.com/browse/NHV-113#icft=NHV-113 and NHV-125: https://github.com/darioquintana/NHibernate-Validator/pull/7