Fix seeking to the end of the buffered data in BufferedStream.

Previously, you could only seek to the final character, and not the
current end of the buffered data.

Author: gsnedders

html5lib/inputstream.py

@@ -63,7 +63,7 @@ def tell(self):
         return pos
 
     def seek(self, pos):
-        assert pos < self._bufferedBytes()
+        assert pos <= self._bufferedBytes()
         offset = pos
         i = 0
         while len(self.buffer[i]) < offset: