Calling .head() on an SFrame with an NDArray is slow

[srikris]

When using in iPython, we can make the NDArray repr faster.

import turicreate
sf = turicreate.SFrame('caltech-101.sframe')
sf['pixel_data'] = sf['image'].apply(lambda x: x.pixel_data)

%timeit sf.head()

It takes a few hundred milliseconds

In [27]: %timeit sf.head()
1 loop, best of 3: 185 ms per loop

[TobyRoseman]

This is still an issue in 6.4