@tensorflowjs/core support

[guybedford]

Importing @tensorflowjs/core currently gives the error:

Uncaught TypeError: this.util.TextEncoder is not a constructor sandbox:2657:349

Within platform_node.js. Example - https://jspm.org/sandbox#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

Tracking issue to investigate and fix this support further.

[guybedford]

I was finally able to fix this issue in jspm/jspm-core#60 and can confirm it is now executing correctly per this sandbox example:

https://jspm.org/sandbox#H4sIAAAAAAAAA61VUU/bMBB+51cc2QtsJG46tLHSIthACETRtlKmPbrJpTFLbMt2KGHaf9/FaSmtWLUHHtrIvvP3fXfnO/e3U5W4WiPkriyOtvqLD/L0aAugX6LjkOTcWHSDoHJZeBB4gxOuwKOx9N+0z9r10xHJSxwE9wJnWhkXQKKkQ0kQM5G6fJDivUgw9Is9EFI4wYvQJrzAQUwEfdYq6E9UWnvU7TCkD8Dl6OsQzlGi4U4ZuCgbfBhy7a1nqXAw/n7Vo3ictj3GpgvX6M7qMhKKvRl3b/Of559/nQ47ph49Xo7GcT46c8Mbd3t9Nbwb17XuDq9PHofu4vFkehpXxc3NxbcTIghDr8UmRmgHTd4GgfAKSq59Xn57GfNNG/TmG7SVcQqYa0E6aDt40sefhEld9p55HXeibjfqskklipSh/cCETPGhOe8x/+y1XDZRGleoXsB+ZiaHY6qFVSYr1Iy57M6GiTK4QdWL/sdx9DHqsFRYt1S2tySZVFmGZhNqs2Aeqht1ok44oZsTxV0mVYqFmFg2MWpm0bAWag0/MbV26lXwW6g1/MYrzNAl+QaOpRNxxE21Wsg1LG1UgnZT4f9f7BxrjcEipobLVJUbSJZORLIfvX+xbs4S3QYQb6fix/tRzPwiosu5BlI5UbxKtA3Q05WnS7+1+G9+fda2YtN58yEBZyMYqrQqEEa5KG1vMSKoQy1oVdSZKArIaHaU3s3CnMrCTLhcVQ7EsxO20n6xw+kUPiRIjf8lN6pEOPj0bndtJHBbywSsSQb/ihxt2PKGtpFHTR53o4O2i9ZsUSlkEzokRllqPzEVchBwqWRdqsoGR+vhr8ylFskPJVhE9JYEQjNiTrSAjIJYHUuHLQ4AY/DDCIeUAiHneaIRntIzgQb3gJJHQBwsak7DFYFyij59tBlQ+AFw54yYVGRTElyOC5RWY+Rp6FGwqsCoUNOduardw5Wy9ln7ANB74B+mv9c/OeiwBgAA