Workaround for #1400. Excludes imported properties from error

[IllusionMH]

As I stated in comment for issue #1400 - difference with TS 2.x because languageService.getDocumentHighlights highlights not only nodes for ITest but also for unknown. I don't know if it is regression in TS or how it is supposed to filtered in new way.

This fix tracks positions for imported properties and prevents errors if it is "highlighted" as use before declarations.

I'd be glad to improve fix if you have any suggestions.

[palantirtech]

Thanks for your interest in palantir/tslint, @IllusionMH! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[IllusionMH]

PR #1608 fixes issue #1400 if linterOptions have "typeCheck": true and both TestInterface.ts and Test are provided.
Therefore this PR is only relevant for typeless (or untyped. What is correct version?) rules.

[nchen63]

@IllusionMH very nice