cleanups after removing Lexicon.pickle

Cython/Compiler/Lexicon.py

 #
-#   Pyrex Scanner - Lexical Definitions
-#
-#   Changing anything in this file will cause Lexicon.pickle
-#   to be rebuilt next time pyrexc is run.
+#   Cython Scanner - Lexical Definitions
 #
 
 raw_prefixes = "rR"

Cython/Compiler/Scanning.py

 #
-#   Pyrex Scanner
+#   Cython Scanner
 #
 
 import os
@@ -20,12 +20,6 @@ from Lexicon import string_prefixes, raw_prefixes, make_lexicon, IDENT
 
 from StringEncoding import EncodedString
 
-try:
-    plex_version = Plex._version
-except AttributeError:
-    plex_version = None
-#print "Plex version:", plex_version ###
-
 debug_scanner = 0
 trace_scanner = 0
 scanner_debug_flags = 0