Remove references to Python2

copy-pasted from pitkajuh. See https://github.com/root-project/cling/pull/519

docs/conf.py

@@ -11,7 +11,6 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-from __future__ import absolute_import, division, print_function
 import sys, os
 from datetime import date
 

docs/tools/in2pod.py

@@ -1,8 +1,7 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # A tool to parse cling.pod.in and generate cling.pod dynamically
 
-from __future__ import print_function
 import subprocess
 import sys
 import os

test/lit.cfg

@@ -13,13 +13,7 @@ from lit.llvm import llvm_config
 
 # Configuration file for the 'lit' test runner.
 
-if sys.version_info < (3, 0):
-    # Python 2.x
-    from urllib2 import urlopen
-    input = raw_input
-else:
-    # Python 3.x
-    from urllib.request import urlopen
+from urllib.request import urlopen
 
 IsWindows = platform.system() == 'Windows'
 

tools/Jupyter/kernel/clingkernel.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 #------------------------------------------------------------------------------
 # CLING - the C++ LLVM-based InterpreterG :)
 # author:  Min RK
@@ -15,8 +15,6 @@ Cling Kernel for Jupyter
 Talks to Cling via ctypes
 """
 
-from __future__ import print_function
-
 __version__ = '0.0.3'
 
 import ctypes

tools/Jupyter/kernel/setup.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # coding: utf-8
 
 #------------------------------------------------------------------------------
@@ -11,8 +11,6 @@
 # LICENSE.TXT for details.
 #------------------------------------------------------------------------------
 
-from __future__ import print_function
-
 # the name of the project
 name = 'clingkernel'
 
@@ -23,13 +21,11 @@ name = 'clingkernel'
 import sys
 
 v = sys.version_info
-if v[:2] < (2,7) or (v[0] >= 3 and v[:2] < (3,3)):
-    error = "ERROR: %s requires Python version 2.7 or 3.3 or above." % name
+if v[0] >= 3 and v[:2] < (3,3):
+    error = "ERROR: %s requires Python version 3.3 or above." % name
     print(error, file=sys.stderr)
     sys.exit(1)
 
-PY3 = (sys.version_info[0] >= 3)
-
 #-----------------------------------------------------------------------------
 # get on with it
 #-----------------------------------------------------------------------------

tools/packaging/cpt.py

@@ -21,10 +21,6 @@
 
 
 import sys
-
-if sys.version_info < (3, 0):
-    raise Exception("cpt needs Python 3")
-
 import argparse
 import copy
 import os