Revert "Revert "Merge branch 'develop' of https://github.com/explosion/spaCy into develop""

This reverts commit f41e626844.

spacy/util.py

@@ -14,6 +14,7 @@ from collections import OrderedDict
 import inspect
 import warnings
 from thinc.neural._classes.model import Model
+from thinc.neural.ops import NumpyOps
 import functools
 import cytoolz
 import itertools
@@ -241,7 +242,12 @@ def is_in_jupyter():
 
 
 def get_cuda_stream(require=False):
-    return CudaStream() if CudaStream is not None else None
+    if CudaStream is None:
+        return None
+    elif isinstance(Model.ops, NumpyOps):
+        return None
+    else:
+        return CudaStream()
 
 
 def get_async(stream, numpy_array):