Several Blip Improvements

This pull request tries to clean up blip a little bit and fixes two issues with stateful address compression from RFC 6282.

Blip has been neglected lately and I'm using it again so I went through and cleaned up comments, interfaces, printf() statements and the like.

The two most recent commits add a little bit more of RFC 6282 that I needed for a certain application.

The older commits are from the blip_interface pull request and only show up here because this PR is based off of that branch, and not master.