Improve a few docstrings in packaging.

Also beautify import lists.  Having them grouped by lenght makes it slightly
easier to look for a module.

Lib/packaging/create.py

-#!/usr/bin/env python
 """Interactive helper used to create a setup.cfg file.
 
 This script will generate a packaging configuration file by looking at
 the current directory and asking the user questions.  It is intended to
-be called as
-
-  pysetup create
-
-or
-
-  python3.3 -m packaging.create
+be called as *pysetup create*.
 """
 
 #  Original code by Sean Reifschneider <jafo@tummy.com>
@@ -26,17 +19,17 @@ or
 #  Detect scripts (not sure how.  #! outside of package?)
 
 import os
+import re
 import imp
 import sys
 import glob
-import re
 import shutil
 import sysconfig
 import tokenize
-from configparser import RawConfigParser
-from textwrap import dedent
 from hashlib import md5
+from textwrap import dedent
 from functools import cmp_to_key
+from configparser import RawConfigParser
 # importing this with an underscore as it should be replaced by the
 # dict form or another structures for all purposes
 from packaging._trove import all_classifiers as _CLASSIFIERS_LIST
@@ -230,7 +223,7 @@ class MainProgram:
         self._write_cfg()
 
     def has_setup_py(self):
-        """Test for the existance of a setup.py file."""
+        """Test for the existence of a setup.py file."""
         return os.path.exists('setup.py')
 
     def define_cfg_values(self):

Lib/packaging/util.py

-"""packaging.util
-Miscellaneous utility functions.
-"""
-import errno
-import csv
-import hashlib
+"""Miscellaneous utility functions."""
+
 import os
-import sys
 import re
+import csv
+import sys
+import errno
 import shutil
 import string
+import hashlib
 import tarfile
 import zipfile
 import posixpath
-import sysconfig
 import subprocess
+import sysconfig
 from glob import iglob as std_iglob
 from fnmatch import fnmatchcase
 from inspect import getsource