Import problem with Python 3.7

[bmilde]

Hi,

we are using puntuator2 in https://github.com/uhh-lt/subtitle2go/ Thanks for creating it!

On Python 3.7 we ran into small problem. Just an FYI, we needed to change punctuator2/models.py on line 54 "from . import models" -> "import models" as the import won't work otherwise and there is an error. Not making a PR because its probably easier if you just change this one line,

Best,

Benjamin

[laosuan]

Python 2.7 also has the same problem, tks!