Major rewrite of definitions section

[dwsideriusNIST]

@mangiapasta : I've done a fairly significant rewrite of the definitions section of the sampling uncertainty paper. My goal was to address the concerns about terminology raised by Dan Z and Paul G, with some major simplifications. I moved some of the more philosophical points to footnotes and then took out repetitive portions.

The other section I cut pretty significantly is your section on "discussion of terminology." Some of your comments should be shifted to footnotes, but I've not yet decided which.

I left all of our old text in commented code for now. Before we do another push to the main repo, let's do a major cleanup of the TeX code.

[SeroNISTPI]

Sounds good. Thanks for letting me know. I'll work on this today and hopefully we can get something back to the group soon.

[SeroNISTPI]

Okay, I went through the definitions today. I will work on the related discussion section tomorrow.

I removed commented notes that seemed obsolete, and I also added a few new comments.