Makefile: add integration tests in ./graph
Makefile: add integration tests in ./graph

- Also export TIMESTAMP so sub-makes get the same
  smoke test data dir.

opentable/sous,opentable/sous,samsalisbury/sous,samsalisbury/sous,samsalisbury/sous,samsalisbury/sous,samsalisbury/sous,opentable/sous,opentable/sous,opentable/sous