Flake8 fixes (#35)

* Apply Flake8 also on `setup.py`

modified:   tox.ini

* Fix W605 - invalid escape syntax

modified:   packages/setup.py
modified:   tox.ini

* Update comment about Flake8: W504

W503 and W504 are mutual exclusive - so we have to keep one of them.

modified:   tox.ini

* Fix F841 - variable assigned but never used

modified:   ssh-audit.py
modified:   tox.ini

* Fix E741 - ambiguous variable name 'l'

modified:   ssh-audit.py
modified:   tox.ini

* Fix E712 - comparison to False should be 'if cond is False'

... and not 'if conf == False'.

modified:   ssh-audit.py
modified:   tox.ini

* Fix E711 - comparison to None should be 'if cond is not None'

... and not 'if cond != None'.

modified:   ssh-audit.py
modified:   tox.ini

* Fix E305 - expected 2 blank lines

... after class or function definition, found 1.

modified:   ssh-audit.py
modified:   tox.ini

* Fix E303 - too many blank lines

modified:   ssh-audit.py
modified:   tox.ini

* Fix E303 - too many blank lines

modified:   ssh-audit.py
modified:   tox.ini

* Fix E301 - expected 1 blank line, found 0

No code change necessary, probably fixed by another commit.

modified:   tox.ini

* Fix E265 - block comment should start with '# '

There is lots of commented out code, which usually should be just
deleted.

I will keep it for now, as I am not yet very familiar with the code
base.

modified:   ssh-audit.py
modified:   tox.ini

* Fix E261 - at least two spaces before inline comment

modified:   ssh-audit.py
modified:   tox.ini

* Fix E251 - unexpected spaces around keyword / parameter equals

modified:   packages/setup.py
modified:   tox.ini

* Fix E231 - missing whitespace after ','

No code change necessary, probably fixed by previous commit.

modified:   tox.ini

* Fix E226 - missing whitespace around arithmetic operator

modified:   ssh-audit.py
modified:   tox.ini

* Fix W293 - blank line contains whitespace

modified:   ssh-audit.py
modified:   tox.ini

* Fix E221 - multiple spaces before operator

modified:   ssh-audit.py
modified:   tox.ini

* Update comment about Flake 8 E241

Lots of data is formatted as tables, so this warning is disabled for a
good reason.

modified:   tox.ini

* Fix E401 - multiple imports on one line

modified:   ssh-audit.py
modified:   tox.ini

* Do not ignore Flake8 warning F401

... as there were no errors in source code anyway.

modified:   tox.ini

* Fix F821 - undefined name

modified:   ssh-audit.py
modified:   tox.ini

* Reformat ignore section for Flake8

modified:   tox.ini

* Flake8 test suite

modified:   test/conftest.py
modified:   test/test_auditconf.py
modified:   test/test_banner.py
modified:   test/test_buffer.py
modified:   test/test_errors.py
modified:   test/test_output.py
modified:   test/test_resolve.py
modified:   test/test_socket.py
modified:   test/test_software.py
modified:   test/test_ssh1.py
modified:   test/test_ssh2.py
modified:   test/test_ssh_algorithm.py
modified:   test/test_utils.py
modified:   test/test_version_compare.py
modified:   tox.ini

test/test_ssh2.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-import struct, os
+import os
+import struct
 import pytest
 
 
@@ -14,7 +15,7 @@ class TestSSH2(object):
 		self.wbuf = ssh_audit.WriteBuf
 		self.audit = ssh_audit.audit
 		self.AuditConf = ssh_audit.AuditConf
-	
+
 	def _conf(self):
 		conf = self.AuditConf('localhost', 22)
 		conf.colors = False
@@ -23,7 +24,7 @@ class TestSSH2(object):
 		conf.ssh1 = False
 		conf.ssh2 = True
 		return conf
-	
+
 	@classmethod
 	def _create_ssh2_packet(cls, payload):
 		padding = -(len(payload) + 5) % 8
@@ -33,7 +34,7 @@ class TestSSH2(object):
 		pad_bytes = b'\x00' * padding
 		data = struct.pack('>Ib', plen, padding) + payload + pad_bytes
 		return data
-	
+
 	def _kex_payload(self):
 		w = self.wbuf()
 		w.write(b'\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff')
@@ -50,7 +51,7 @@ class TestSSH2(object):
 		w.write_byte(False)
 		w.write_int(0)
 		return w.write_flush()
-	
+
 	def test_kex_read(self):
 		kex = self.ssh2.Kex.parse(self._kex_payload())
 		assert kex is not None
@@ -69,7 +70,7 @@ class TestSSH2(object):
 		assert kex.server.languages == [u'']
 		assert kex.follows is False
 		assert kex.unused == 0
-	
+
 	def _get_empty_kex(self, cookie=None):
 		kex_algs, key_algs = [], []
 		enc, mac, compression, languages = [], [], ['none'], []
@@ -80,7 +81,7 @@ class TestSSH2(object):
 			cookie = os.urandom(16)
 		kex = self.ssh2.Kex(cookie, kex_algs, key_algs, cli, srv, 0)
 		return kex
-	
+
 	def _get_kex_variat1(self):
 		cookie = b'\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff'
 		kex = self._get_empty_kex(cookie)
@@ -123,12 +124,12 @@ class TestSSH2(object):
 				continue
 			kex.client.compression.append(a)
 		return kex
-	
+
 	def test_key_payload(self):
 		kex1 = self._get_kex_variat1()
 		kex2 = self.ssh2.Kex.parse(self._kex_payload())
 		assert kex1.payload == kex2.payload
-	
+
 	@pytest.mark.skip(reason="Temporarily skip this test to have a working test suite!")
 	def test_ssh2_server_simple(self, output_spy, virtual_socket):
 		vsocket = virtual_socket