Update pycrumbs.md
Update pycrumbs.md
Merge pull request #62 from sant0sh/master

Updated 'Online courses' to 'Online Courses and Challenges'
Fixed merge conflicts
Update authors.md
Update pycrumbs.md

added a django book (Tango with Django)
Merge pull request #63 from dhirajt/master

Added a django book - tango with django
Update pycrumbs.md
Merge pull request #64 from dhirajt/master

Added django screencast site - godjango.com
Added learn python link
Removed empty link
Added 2 links under Django
Add Classy Class-Based Views
Merge pull request #65 from imom0/patch-1

Add Classy Class-Based Views
Added an author

Added Yang Yang as a contributor.
Add IPython notebooks
Merge pull request #67 from ds604/master

Add IPython notebooks