In setup.py, switch from distutils to setuptools and declare Python 3 okay

Signed-off-by: David A. Wheeler <dwheeler@dwheeler.com>

setup.py

@@ -3,29 +3,14 @@
 # This is the setup.py script for "flawfinder" by David A. Wheeler.
 # My thanks to Jon Nelson, who created the initial setup.py script.
 
-# Template for creating your own setup.py.  See the USAGE file in
-# the Distutils source distribution for descriptions of all the
-# options shown below.  Brief instructions on what to do:
-#   - set the other metadata: version, description, author, author_email
-#     and url.  All of these except 'description' are required, although
-#     you may supply 'maintainer' and 'maintainer_email' in place of (or in
-#     addition to) 'author' and 'author_email' as appropriate.
-#   - fill in or delete the 'packages', 'package_dir', 'py_modules',
-#     and 'ext_modules' options as appropriate -- see USAGE for details
-#   - delete this comment and change '__revision__' to whatever is
-#     appropriate for your revision control system of choice (just make
-#     sure it stores the revision number for your distribution's setup.py
-#     script, *not* the examples/template_setup.py file from Distutils!)
-
-
 """Setup script for the flawfinder tool."""
 
-from distutils.core import setup
-import commands
+from setuptools import setup # Don't need find_packages
 
 setup (# Distribution meta-data
        name = "flawfinder",
        packages = ["flawfinder"], # Must be same as name
+       # Do not need: packages=find_packages(),
        version = "2.0.2",
        description = "a program that examines source code looking for security weaknesses",
        author = "David A. Wheeler",
@@ -37,6 +22,7 @@ ranking them by likely severity.
 It is released under the GNU GPL license.""",
        url = "http://www.dwheeler.com/flawfinder/",
        download_url = "https://sourceforge.net/projects/flawfinder/files/flawfinder-2.0.2.tar.gz/download",
+       zip_safe = True,
        keywords = ['analysis', 'security', 'analyzer'],
        classifiers = [
            'Development Status :: 5 - Production/Stable',
@@ -45,13 +31,15 @@ It is released under the GNU GPL license.""",
            'License :: OSI Approved :: GNU General Public License v2 or later (GPLv2+)',
            'Natural Language :: English',
            'Programming Language :: Python :: 2.7',
+           'Programming Language :: Python :: 3',
+           'Programming Language :: Python :: 3.6',
            'Operating System :: OS Independent',
            'Topic :: Security',
            'Topic :: Software Development :: Build Tools',
            'Topic :: Software Development :: Quality Assurance',
            'Topic :: Software Development :: Testing'
            ],
-       python_requires = '~=2.7',
+       python_requires = '>=2.7',
        scripts = [ 'flawfinder' ],
        data_files = [ ('share/man/man1', [ 'flawfinder.1.gz' ]) ],
        py_modules = [ ],