Fixpoint returned graph contains original edge attributes
Test_int is a bit more complex

not completely trivial to prove that resulting y is positive
Fix: distinguish different call sites within the same stack
Fix external functions having inputs included in vertex

And a few more asserts
Add dot generation to main
Forgot to add a test
Merge pull request #5 from chambart/master

Quelques petits trucs
Fix a problem that occured on function calling.