Not Python3 compatible

[elzibubble]

  File "bin/dot", line 31, in <module>
    from dot import COMMANDS
  File "/home/alee/.dotfiles/bin/lib/dot/__init__.py", line 2, in <module>
    from .core import COMMANDS
  File "/home/alee/.dotfiles/bin/lib/dot/core.py", line 486
    print env
            ^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print(env)?

I see you just changed the shebang from python2 to python, so I won't propose changing that back. Maybe you could import print_function from __future__; or simply move to Py3 as Py2 will be EOL soon anyway?

[svetlyak40wt]

Feel free to make a pull-request. Probably, a separate branch for python3 could be used to not support both pythons simultaneously.