Corrected to write bytes instead of strings

TileStache/Core.py

@@ -146,10 +146,10 @@
 import logging
 from wsgiref.headers import Headers
 try:
-    from io import StringIO
+    from io import BytesIO
 except ImportError:
     # Python 2
-    from StringIO import StringIO
+    from StringIO import StringIO as BytesIO
 try:
     from urllib.parse import urljoin
 except ImportError:
@@ -425,7 +425,7 @@ def getTileResponse(self, coord, extension, ignore_cached=False):
 
                 if body is None:
                     # No one else wrote the tile, do it here.
-                    buff = StringIO()
+                    buff = BytesIO()
 
                     try:
                         tile = self.render(coord, format)

TileStache/Providers.py

@@ -74,10 +74,10 @@
 import logging
 
 try:
-    from io import StringIO
+    from io import BytesIO
 except ImportError:
     # Python 2
-    from StringIO import StringIO
+    from StringIO import StringIO as BytesIO
 from string import Template
 try:
     import urllib.request as urllib2
@@ -148,7 +148,7 @@ class Verbatim:
     ''' Wrapper for PIL.Image that saves raw input bytes if modes and formats match.
     '''
     def __init__(self, bytes):
-        self.buffer = StringIO(bytes)
+        self.buffer = BytesIO(bytes)
         self.format = None
         self._image = None