Some work lesson 6
Fix wrong after-refactoring value
Add session 6. Not tested yet
Add sunspot example code
Fix bugs in python files when run
Fix dexy run
Minor fixes
Slides and notebook for session 6, notebook links
Double path in URLs to work around stupid relative link regexp problem
Double path in URLs to work around stupid relative link regexp problem
Various fixes
Various fixes
Revert "Hide future lessons again on master branch"

This reverts commit 9dff541b359bab37cdfc60adfec1638c8168ac93.
Merge branch 'staging'

* staging:
  Various fixes
  Double path in URLs to work around stupid relative link regexp problem
  Double path in URLs to work around stupid relative link regexp problem
  Slides and notebook for session 6, notebook links
  Minor fixes
  Fix dexy run
  Fix bugs in python files when run
  Add sunspot example code
  Add session 6. Not tested yet
  Fix wrong after-refactoring value
  Some work lesson 6
Rehide future lessons