Portable Python script across Python version

Make scripts more future-proof by importing most __future__ stuff.

Differential Revision: https://reviews.llvm.org/D55208

git-svn-id: svn://svn.chromium.org/llvm-project/cfe/trunk/tools/clang-format@349504 0b72dbe1-c17f-4bc7-b9db-2b4152be0356
diff --git a/clang-format-diff.py b/clang-format-diff.py
index 1721d8a..54347ce 100755
--- a/clang-format-diff.py
+++ b/clang-format-diff.py
@@ -21,7 +21,7 @@
   svn diff --diff-cmd=diff -x-U0 | clang-format-diff.py -i
 
 """
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 
 import argparse
 import difflib
diff --git a/clang-format-sublime.py b/clang-format-sublime.py
index 16ff56e..5ea9a27 100644
--- a/clang-format-sublime.py
+++ b/clang-format-sublime.py
@@ -12,7 +12,7 @@
 # It operates on the current, potentially unsaved buffer and does not create
 # or save any files. To revert a formatting, just undo.
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 import sublime
 import sublime_plugin
 import subprocess
diff --git a/clang-format.py b/clang-format.py
index 5fe592a..fe068bd 100644
--- a/clang-format.py
+++ b/clang-format.py
@@ -25,7 +25,7 @@
 #
 # It operates on the current, potentially unsaved buffer and does not create
 # or save any files. To revert a formatting, just undo.
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 
 import difflib
 import json
diff --git a/git-clang-format b/git-clang-format
index 0b21039..96e3b4e 100755
--- a/git-clang-format
+++ b/git-clang-format
@@ -23,7 +23,7 @@
 Requires Python 2.7 or Python 3                                                  
 """               
 
-from __future__ import print_function
+from __future__ import absolute_import, division, print_function
 import argparse
 import collections
 import contextlib