Bugfix-- Why does raw_models metadata blobs fail?

[gully]

Traceback (most recent call last):
  File "/Users/gully/GitHub/protostars//code/star_protostars_Av.py", line 216, in <module>
    np.save('temp_raw_models.npy',sampler.blobs)
  File "//anaconda/envs/Starfish/lib/python3.5/site-packages/numpy/lib/npyio.py", line 491, in save
    pickle_kwargs=pickle_kwargs)
  File "//anaconda/envs/Starfish/lib/python3.5/site-packages/numpy/lib/format.py", line 573, in write_array
    pickle.dump(array, fp, protocol=2, **pickle_kwargs)
OSError: [Errno 22] Invalid argument