Talked about deficiencies of ebooks and pdfs for re-authoring equations.
Splitting up paragraphs.
Wanted to jot some ideas down, but didn't have time to flesh them out, so left them as LaTeX comments.
Some typo fixing and more thorough discussion.
Expanded sections discussing conflicting units systems. Also removed pdf so that it isn't the old version.  I'll only include pdfs when I push to GitHub.
Changed spec.tex to description.tex, since this is a general overview, not a formal specification.
Some quick editing I forgot to commit earlier.