Address "UNFINISHED" PDU's

[Leif Gruenwoldt]

A number of PDU's have a comment in the header that says they are "UNFINISHED". Each of these comments will need to be reviewed to determine what if anything is still required. In some cases, the comment may simply be outdated. In other cases, code changes may be required.

If we do a code search for the UNFINISHED string on GitHub we can see these results:

https://github.com/search?q=repo%3Aopen-dis%2Fopen-dis-java%20UNFINISHED&type=code