Add more latex commands, remove empty trailing or leading lines in source.
Add some python syntax helpers.
Merge branch 'master' of https://github.com/gpeyre/numerical-tours

* 'master' of https://github.com/gpeyre/numerical-tours:
  added gradient computation
  update readme
  update readme
  updated readme.
  update readme.
  Update Readme.
  update readme
  update readme
  Update active contours
Merge pull request #7 from blink1073/master

Improvements to Matlab -> Notebook Conversion