[DFDL-WG] proposal: errata: add rawbytes as optional feature

I believe rawbytes should be an optional feature. It is a quite complex feature to implement, and many implementations may not want to bother. Also since lengthKind='delimited' is optional, and that is the primary use case for rawBytes, I think we should be consistent and add rawbytes to the list of optional features. ...mike -- Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com