Merge pull request #1397 from shoyer/const

Fix incorrect const qualifier in membuf.pyx

Author: Jeff Whitaker

include/membuf.pyx

@@ -14,7 +14,7 @@ cdef memview_fromptr(void *memory, size_t size):
 
 # private extension type that implements buffer protocol.
 cdef class _MemBuf:
-    cdef const void *memory
+    cdef void *memory
     cdef size_t size
     def __getbuffer__(self, Py_buffer *buf, int flags):
         PyBuffer_FillInfo(buf, self, <void *>self.memory, self.size, 1, flags)