Apply PEP 8 style guidance to zenmap

Using the pep8 tool (https://pypi.python.org/pypi/pep8), fixed the
following style issues:

Count   Issue
11      E201 whitespace after '['
8       E203 whitespace before ','
41      E211 whitespace before '('
11      E221 multiple spaces before operator
61      E225 missing whitespace around operator
237     E231 missing whitespace after ':'
91      E251 no spaces around keyword / parameter equals
19      E261 at least two spaces before inline comment
41      E301 expected 1 blank line, found 0
200     E302 expected 2 blank lines, found 1
356     E303 too many blank lines (2)
563     E501 line too long (106 characters)
39      E701 multiple statements on one line (colon)
13      E702 multiple statements on one line (semicolon)
4       W291 trailing whitespace
2       W293 blank line contains whitespace
8       W391 blank line at end of file
21      W601 .has_key() is deprecated, use 'in'
2       W602 deprecated form of raising exception

The remaining issues are long lines due to very deep data structures. I
chose not to alter them, as it would involve backslash-continuation
where whitespace is not permitted:

./zenmapGUI/ScanInterface.py:323:80: E501 line too long (90 characters)
./zenmapGUI/ScanInterface.py:456:80: E501 line too long (84 characters)
./zenmapGUI/ScanInterface.py:464:80: E501 line too long (84 characters)
./zenmapGUI/ScanInterface.py:472:80: E501 line too long (122 characters)
./zenmapGUI/ScanInterface.py:479:80: E501 line too long (122 characters)
./zenmapGUI/ScanInterface.py:920:80: E501 line too long (94 characters)
./zenmapGUI/ScanInterface.py:923:80: E501 line too long (93 characters)
./zenmapGUI/MainWindow.py:575:80: E501 line too long (99 characters)
./zenmapGUI/MainWindow.py:906:80: E501 line too long (99 characters)

zenmap/zenmapCore/Paths.py

@@ -133,6 +133,7 @@ from zenmapCore.Version import VERSION
 from zenmapCore.Name import APP_NAME
 from zenmapCore.UmitOptionParser import option_parser
 
+
 # Find out the prefix under which data files (interface definition XML,
 # pixmaps, etc.) are stored. This can vary depending on whether we are running
 # in an executable package and what type of package it is, which we check using
@@ -161,6 +162,8 @@ MISC_DIR = join(prefix, "share", APP_NAME, "misc")
 PIXMAPS_DIR = join(prefix, "share", "zenmap", "pixmaps")
 DOCS_DIR = join(prefix, "share", APP_NAME, "docs")
 NMAPDATADIR = join(prefix, "..")
+
+
 def get_extra_executable_search_paths():
     """Return a list of additional executable search paths as a convenience for
     platforms where the default PATH is inadequate."""
@@ -170,6 +173,7 @@ def get_extra_executable_search_paths():
         return [dirname(sys.executable)]
     return []
 
+
 #######
 # Paths
 class Paths(object):
@@ -194,7 +198,8 @@ class Paths(object):
 
     def __init__(self):
         self.user_config_dir = option_parser.get_confdir()
-        self.user_config_file = os.path.join(self.user_config_dir, base_paths['user_config_file'])
+        self.user_config_file = os.path.join(
+                self.user_config_dir, base_paths['user_config_file'])
         self.config_dir = CONFIG_DIR
         self.locale_dir = LOCALE_DIR
         self.pixmaps_dir = PIXMAPS_DIR
@@ -207,10 +212,12 @@ class Paths(object):
             return self.__dict__[name]
 
         elif name in self.config_files_list:
-            return return_if_exists(join(self.user_config_dir, base_paths[name]))
+            return return_if_exists(
+                    join(self.user_config_dir, base_paths[name]))
 
         elif name in self.empty_config_files_list:
-            return return_if_exists(join(self.user_config_dir, base_paths[name]), True)
+            return return_if_exists(
+                    join(self.user_config_dir, base_paths[name]), True)
 
         elif name in self.misc_files_list:
             return return_if_exists(join(self.misc_dir, base_paths[name]))
@@ -223,15 +230,17 @@ class Paths(object):
     def __setattr__(self, name, value):
         self.__dict__[name] = value
 
+
 def create_dir(path):
     """Create a directory with os.makedirs without raising an error if the
-        directory already exists."""
+    directory already exists."""
     try:
         os.makedirs(path)
     except OSError, e:
         if e.errno != errno.EEXIST:
             raise
 
+
 def create_user_config_dir(user_dir, template_dir):
     """Create a user configuration directory by creating the directory if
     necessary, then copying all the files from the given template directory,
@@ -253,6 +262,7 @@ def create_user_config_dir(user_dir, template_dir):
         shutil.copyfile(template_filename, user_filename)
         log.debug(">>> Copy %s to %s." % (template_filename, user_filename))
 
+
 def return_if_exists(path, create=False):
     path = os.path.abspath(path)
     if os.path.exists(path):