bpo-25324: copy tok_name before changing it (#1608)

* add test to check if were modifying token

* copy list so import tokenize doesnt have side effects on token

* shorten line

* add tokenize tokens to token.h to get them to show up in token

* move ERRORTOKEN back to its previous location, and fix nitpick

* copy comments from token.h automatically

* fix whitespace and make more pythonic

* change to fix comments from @haypo

* update token.rst and Misc/NEWS

* change wording

* some more wording changes
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index 9017bb1..5fa4152 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -38,17 +38,10 @@
 blank_re = re.compile(br'^[ \t\f]*(?:[#\r\n]|$)', re.ASCII)
 
 import token
-__all__ = token.__all__ + ["COMMENT", "tokenize", "detect_encoding",
-                           "NL", "untokenize", "ENCODING", "TokenInfo"]
+__all__ = token.__all__ + ["tokenize", "detect_encoding",
+                           "untokenize", "TokenInfo"]
 del token
 
-COMMENT = N_TOKENS
-tok_name[COMMENT] = 'COMMENT'
-NL = N_TOKENS + 1
-tok_name[NL] = 'NL'
-ENCODING = N_TOKENS + 2
-tok_name[ENCODING] = 'ENCODING'
-N_TOKENS += 3
 EXACT_TOKEN_TYPES = {
     '(':   LPAR,
     ')':   RPAR,