[analyzer] Remove Python 2 code (#243).

Support for Python 2 in IKOS was removed in a prior commit dealing with python
package installation.

This commit adjusts Python modules to remove any logic pertaining to Python 2.
More specifically:

- The imports in `http` are adjusted.
- The module `html`, which was a wrapper around the standard `html`, is removed.
- Other modules that were importing `ikos.html` now import `html` directly.
- Remove a comment in `output_db` referring to Python 2.

analyzer/python/ikos/highlight.py

@@ -39,7 +39,8 @@
 # UNILATERAL TERMINATION OF THIS AGREEMENT.
 #
 ###############################################################################
-from ikos import html
+import html
+
 from ikos import log
 
 

analyzer/python/ikos/http.py

@@ -39,21 +39,13 @@
 # UNILATERAL TERMINATION OF THIS AGREEMENT.
 #
 ###############################################################################
-try:
-    # Python 3
-    from http.server import HTTPServer, BaseHTTPRequestHandler
-    from urllib.parse import parse_qs, urlencode
-    from urllib.request import urlopen
-except ImportError:
-    # Python 2
-    from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
-    from urlparse import parse_qs
-    from urllib import urlencode
-    from urllib2 import urlopen
 
+import os
 from errno import EAFNOSUPPORT
+from http.server import HTTPServer, BaseHTTPRequestHandler
 from socket import AF_INET, AF_INET6
-import os
+from urllib.parse import parse_qs, urlencode
+from urllib.request import urlopen
 
 class HTTPServerIPv6(HTTPServer):
     '''

analyzer/python/ikos/output_db.py

@@ -68,7 +68,7 @@ def __init__(self, path):
         self.con = sqlite3.connect(path)
 
         # Use 'str' as text factory since it's the type of string literals
-        # This is bytes in python 2 and unicode in python 3
+        # This is unicode
         self.con.text_factory = str
 
     def close(self):

analyzer/python/ikos/view.py

@@ -43,6 +43,7 @@
 ###############################################################################
 import argparse
 import collections
+import html
 import io
 import json
 import operator
@@ -56,7 +57,6 @@
 
 from ikos import args
 from ikos import colors
-from ikos import html
 from ikos import log
 from ikos import report
 from ikos import settings