Revert "NotesOnLaTeX.ipynb"

This reverts commit 089445717e1d4aed17da910a8f194602ab1dc326.
Revert "Revert "NotesOnLaTeX.ipynb""

This reverts commit f9f2646d1117e6ff4101c7f2b31dbb6c0a402509.
update file .gitignore