Using with power-assert

I would like to use [power-assert]( https://github.com/power-assert-js/espower-typescript) for testing, but it conflicts with truffle-typings definitions.

1. You need to require `assert` in your module and the module asserts get rewritten

2. `assert` is already declared by `truffle-typings` as const and cannot be overwritten as import

Any good ideas how to work around this?

```
TSError: ⨯ Unable to compile TypeScript:
test/Token.spec.ts:4:7 - error TS2451: Cannot redeclare block-scoped variable 'assert'.

4 const assert = require("assert"); // Power assert https://github.com/power-assert-js/espower-typescript
~~~~~~

node_modules/truffle-typings/index.d.ts:10:15
10 declare const assert: Chai.AssertStatic;
~~~~~~
'assert' was also declared here.
```

Reproduce the compiler error from test/Token.spec.ts and inspect the conflicting declaration in node_modules/truffle-typings/index.d.ts. Trace how the ambient assert declaration is exposed and how power-assert rewrites the required module; done means the TypeScript test setup can use power-assert without TS2451.

Written by the indexing model from the issue text.