Changed xmlfiles element for files (xmlfiles is invalid xml), added support for FailOnError to ValidateXml task.
Changed xmlfiles element for files (xmlfiles is invalid xml), added support for FailOnError to ValidateXml task.

nant/nantcontrib,dahmage/nantcontrib,nant/nantcontrib,cgourlay/nantcontrib,rmboggs/nantcontrib,cgourlay/nantcontrib,dahmage/nantcontrib,cgourlay/nantcontrib,rmboggs/nantcontrib,dahmage/nantcontrib,rmboggs/nantcontrib,nant/nantcontrib