Destructured imports can cause compilation failures in .d.ts files

[sjbarag]

Splitshot does not handle destructured imports very well right now. It works alright if you've only got one of them, but it names the imported item "". This creates an issue once you have two imports like this in one file, as Splitshot names both of them "".

{ join } = require("path");
{ readFile } = require("fs");

Error message: error TS2300: Duplicate identifier '_'.

Note that the error message doesn't occur until compiling a project with Splitshot's output, as the TypeScript compiler itself complains about the duplicate _ consts that get declared.