Merge pull request #4 from icyfenix/master

Data Modeling
index
renamed dirs
merged her changes
links
Multimedia slides
Graphics slides
Graphics exercises
Slide changes
More graphics changes
Update graphics/index.html

Cackgrounds -> Backgrounds 
Update graphics/index.html

crackgrounds -> backgrounds, double checked.
Merge pull request #11 from aravasio/patch-3

Update graphics/index.html
Local storage slides
Merge branch 'master' of github.com:pamelafox/teaching-materials
Add workshop page
WebGL exercise
Meme generator and exercise renames
IndexedDB exercise
More updates