Did some minor clean up, and made a simplification.

"=" automatically returns the foldlevel of the previous line, so the bottom
of "LatexBox_FoldLevel" was simplified accordingly.
Some more updates to folding

* It may be that Randy and I should have a discussion about some of the folding
  ideas.  I disagree with some of his updates, and I have reverted to an older
  version with regard to
  1. should not add space between folds for parts
  2. should not fold begin/end{document}
  3. removed the detect_fold_level function, as it is not needed
* I also added folding for fake sections, as it is a nice functionality in some
  cases (I will add text about this in the help file)
Big update to fold text

Note that this is also a minor return to the style I added in
September/October, although it has been improved since then.