convert experiment table to pandas and numpy objects

[gfursin]

when retrieving experiment table (ck get experiment:), add option to convert tables (currently as list of vectors) into pandas or numpy objects

Moved from CK: mlcommons/ck#21

[psyhtest]

Hmm, CK users now routinely do this for various analysis workflows, especially with Jupyter notebooks.

[gfursin]

I meant more to create a universal and reusable API to convert CK experiment to padas/numpy objects ...