[add] node.detatch()
[fix] node.childrens() not children()
[add] node.childrens_iterator(), node.childrens_tree() and node.is_child() (defines graph accesibility)
[todo] add some bactracking on node.childrens_iterator()
Merge remote-tracking branch 'titou/master'
Merge branch 'master' of https://github.com/C4ptainCrunch/whiteboard
[fix] Use --urlprefix again
[fix] missing trailing /related for keywords URL
[fix] Add .sass-cache to ignored files
[add] Now the graph SVG is index page
Now course description is rendered as Markdown