Update @tensorflow/tfjs to 1.7.0

[bomanimc]

This PR updates tfjs to the most recent minor version (1.7.0, though the patch 1.7.1 is out but not yet supported by FaceAPI). In addition, I needed to:

• Update the faceApi version number
• Update away from using Tf.Tensor.make to using the new Tensor creation syntax (https://js.tensorflow.org/api/latest/#tensor)

This will allow us to update the versions of some of our other models, but I'll save those changes for later PRs.

Updated Build Sizes

Built at: 3/31/2020 1:26:48 AM
         Asset      Size  Chunks                    Chunk Names
    ml5.min.js  2.35 MiB    0, 1  [emitted]  [big]  ml5.min
        ml5.js  4.91 MiB    1, 0  [emitted]  [big]  ml5
ml5.min.js.map  7.37 MiB    0, 1  [emitted]         ml5.min
    ml5.js.map  5.79 MiB    1, 0  [emitted]         ml5

It looks like this caused some changes in build size. Comparison to current sizes in 0.5.0 (https://unpkg.com/browse/[email protected]/dist/)
ml5.min.js -> 2.67 MB
ml5.js -> 5.6 MB
ml5.min.js.map -> 8.45 MB
ml5.js.map -> 6.62 MB

This cuts our minified distribution down by 0.32MB!

Testing Process

• Ran yarn test-travis and saw no errors
• Manually test the CharRNN and FaceApi examples to ensure they were still functioning.

[joeyklee]

Excellent! Great to see that these changes have fixed some issues and also reduced the size of the lib. Thank you for addressing this!

[joeyklee]

Merging in now!