Properly warn for E262 with non breaking whitespaces

Closes #1034

Author: Pierre-Sassoulas

pycodestyle.py

@@ -126,7 +126,7 @@ def lru_cache(maxsize=128):  # noqa as it's a fake implementation.
     '%=', '^=', '&=', '|=', '==', '<=', '>=', '<<=', '>>=', '=',
     'and', 'in', 'is', 'or', '->'] +
     ASSIGNMENT_EXPRESSION_OP)
-WHITESPACE = frozenset(' \t')
+WHITESPACE = frozenset(' \t\xa0')
 NEWLINE = frozenset([tokenize.NL, tokenize.NEWLINE])
 SKIP_TOKENS = NEWLINE.union([tokenize.INDENT, tokenize.DEDENT])
 # ERRORTOKEN is triggered by backticks in Python 3
@@ -1056,7 +1056,7 @@ def whitespace_around_named_parameter_equals(logical_line, tokens):
 
 @register_check
 def whitespace_before_comment(logical_line, tokens):
-    r"""Separate inline comments by at least two spaces.
+    """Separate inline comments by at least two spaces.
 
     An inline comment is a comment on the same line as a statement.
     Inline comments should be separated by at least two spaces from the
@@ -1069,10 +1069,11 @@ def whitespace_before_comment(logical_line, tokens):
     Okay: x = x + 1    # Increment x
     Okay: # Block comments:
     Okay: #  - Block comment list
-    Okay: #  - Block comment list
+    Okay: # \xa0- Block comment list
     E261: x = x + 1 # Increment x
     E262: x = x + 1  #Increment x
     E262: x = x + 1  #  Increment x
+    E262: x = x + 1  # \xa0Increment x
     E265: #Block comment
     E266: ### Block comment
     """

testsuite/E26.py

@@ -57,3 +57,10 @@ def oof():
     # ################################################################ #
     # ####################### another separator ###################### #
     # ################################################################ #
+#: E262:3:9
+# -*- coding: utf8 -*-
+#  (One space one NBSP) Ok for block comment
+a = 42  #  (One space one NBSP)
+#: E262:2:9
+#  (Two spaces) Ok for block comment
+a = 42  #  (Two spaces)