Adding Swift Language Bindings.

[RockfordWei]

https://github.com/PerfectlySoft/Perfect-TensorFlow
Supports Swift 3.1/4.0 on both macOS / Ubuntu Linux, with full documentation and example.

[googlebot]

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[tensorflow-jenkins]

Can one of the admins verify this patch?

[RockfordWei]

Just signed the CLA, please check it out, Thank you!

[drpngx]

@RockfordWei I can't see the CLA in our database. It's associated with email. Could you check again?

Thanks.

[RockfordWei]

@drpngx Yes, I did sign the document and the email address is 100% matched with my google developer account. The CLA is terrible - not editable, actually, so I had to sign both documents for individual and on behalf my employer and I can review them in any moment online. Do you need my envelope id?

[googlebot]

CLAs look good, thanks!

[drpngx]

Jenkins, test this please.