dtslint it pinned, either rework TS lint step or scrap it

[tbeseda]

In an ideal world we could update dtslint from 0.0.115 to 0.0.116 and beyond, but something fundamentally changed about the utility at that point.

Others have pinned:

IMO, that works for now but is not sustainable in the TS world that continues to spin.

3 options:

1. find out what happened in dtslint and try to keep up (if only there was a changelog...) https://github.com/microsoft/DefinitelyTyped-tools/tree/master/packages/dtslint
2. swap to tsd which seems to be simpler and more popular https://github.com/SamVerschueren/tsd
3. skip testing TS type defs -- not my favorite

I'm leaning toward option 2 and have assigned myself here, but any and all input is welcome. 🥂