Drop support for Python 2.

src/ifcopenshell-python/ifcopenshell/__init__.py

@@ -30,10 +30,6 @@ Example:
     model = ifcopenshell.open("/path/to/model.ifc")
 """
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-
 import os
 import sys
 import zipfile