Adjustments to setup.py and README for torch Sobol (#55)

[Balandat]

Summary:
Pull Request resolved: pytorch/botorch#55

Using the torch native SobolEngine makes things a lot simpler for botorch.
ax still uses the cython SobolEngine for a lot of things outside torch land.

Reviewed By: danielrjiang

Differential Revision: D14946543

[Balandat]

Anyone has any idea why this is failing with the following? Seems totally unrelated. Maybe an infra failure? Will rerun

pip 19.0.3 from /home/travis/virtualenv/python3.7.1/lib/python3.7/site-packages/pip (python 3.7)
0.01s$ openssl aes-256-cbc -K $encrypted_39ecd60da1dc_key -iv $encrypted_39ecd60da1dc_iv -in botorch_key.enc -out botorch_key -d
iv undefined
The command "openssl aes-256-cbc -K $encrypted_39ecd60da1dc_key -iv $encrypted_39ecd60da1dc_iv -in botorch_key.enc -out botorch_key -d" failed and exited with 1 during .

[Balandat]

Oh I see I cut off the message too early - the encrypted environment variable is not available since this PR came from a fork .... not sure it's worth figuring out how to fix this since things will be made public soon anyway. I'll send a throwaway pr from the actual repo for testing onluy

[facebook-github-bot]

This pull request has been merged in 1fefa18.