Finished tree indexing slides and removed unnecessary diagrams
Merge branch 'master' of https://github.com/OpenDSA/OpenDSA
Fixed sintax errors and alignment
Created khan academy exercise for tree indexing.
Removed unnecessary code from js file
Added new khan academy exercise to module and remove old/unnecesary content
Merge branch 'master' of https://github.com/OpenDSA/OpenDSA