prettify foursquare module a bit

tests/foursquare.py

@@ -0,0 +1,7 @@
+from my.foursquare import get_checkins
+
+def test_checkins():
+    checkins = get_checkins()
+    assert len(checkins) > 100
+    assert any('Victoria Park' in c.summary for c in checkins)
+    # TODO cid_map??