Git-dag broken on python3

[andrewcchen]

Version: git master
Stacktrace:

$ ./bin/git-dag 
Traceback (most recent call last):
  File "./bin/git-dag", line 91, in <module>
    sys.exit(main())
  File "./bin/git-dag", line 63, in main
    return args.func(args)
  File "./bin/git-dag", line 86, in cmd_dag
    view = git_dag(context.model, args=args, settings=args.settings)
  File "/home/andrew/git-cola/cola/widgets/dag.py", line 42, in git_dag
    view = GitDAG(model, ctx, settings=settings)
  File "/home/andrew/git-cola/cola/widgets/dag.py", line 398, in __init__
    defs.spacing)
  File "/home/andrew/git-cola/cola/qtutils.py", line 55, in hbox
    return box(QtGui.QHBoxLayout, margin, spacing, *items)
  File "/home/andrew/git-cola/cola/qtutils.py", line 83, in box
    elif isinstance(i, (int, long)):
NameError: name 'long' is not defined