Improve stack trace
Import traceback module
HUGE bug fixed ;) Fix #112
Savepoints for IntegrityError.

Maybe related to #114
Threshold for old avatar
Update fuzzy test
Birth is not an auto_add anymore
Reimplement agraph.Graph from pygraphviz
Removed pygraphviz from dependencies
Display dependencies as svg
Dead code
Restore non existing nodes in red
Add title
Merge branch 'master' into crons