Update ansitowin32.py to use raw string for re pattern

Same change as for sensei.py

Author: millerabel

libs/colorama/ansitowin32.py

@@ -40,7 +40,7 @@ class AnsiToWin32(object):
     sequences from the text, and if outputting to a tty, will convert them into
     win32 function calls.
     '''
-    ANSI_RE = re.compile('\033\[((?:\d|;)*)([a-zA-Z])')
+    ANSI_RE = re.compile(r'\033\[((?:\d|;)*)([a-zA-Z])')
 
     def __init__(self, wrapped, convert=None, strip=None, autoreset=False):
         # The wrapped stream (normally sys.stdout or sys.stderr)