AVL (broken)
Update make test target.
Print more debug info.
Thomas please don't use tabs.
Fix the bug in the AVL rebalancing functions.
Implement deletion + missing file, sorry about that.

I'm unsure as to whether we're testing removal of the values that we added
before. Is there a way to guarantee that? I'm unsure that the framework is
properly checking my delete function, we should probably talk about it.
Merge pull request #23 from braibant/graph-based

Graph based