Skip metadata files which start with a namespace and end in __c.  This
specifically applies to extending a custom object from another namespace
to add subtypes to it.  In that case, we don't want the CustomObject
included in package.xml as it will cause a deployment failure
Merge pull request #632 from SalesforceFoundation/feature/skip-namespaced-metadata

Allow extending CustomObject from another package
Merge dev into feature/575-error-notifications-validation