remove unused Token and add parent attribute

Adding a parent attribute helped but wasn't working with amalgamated
xonsh -- turns out there's a separate Token definition in tokenize that
is never used but does redefine Token once it's hit -- this was causing
crashes on my end.

xonsh/style_tools.py

@@ -11,6 +11,8 @@ class _TokenType(tuple):
     This class was forked from the mainline prompt-toolkit repo.
     Copyright (c) 2014, Jonathan Slenders, All rights reserved.
     """
+    parent = None
+
     def __getattr__(self, val):
         if not val or not val[0].isupper():
             return tuple.__getattribute__(self, val)

xonsh/tokenize.py

@@ -249,7 +249,6 @@ Special = group(r'\r?\n', r'\.\.\.', r'[:;.,@]')
 Funny = group(Operator, Bracket, Special)
 
 PlainToken = group(IORedirect, Number, Funny, String, Name_RE, SearchPath)
-Token = Ignore + PlainToken
 
 # First (or only) line of ' or " string.
 ContStr = group(StringPrefix + r"'[^\n'\\]*(?:\\.[^\n'\\]*)*" +