Left hand side of For...of cannot use type annotation, but tslint requires it

[BuffCoder]

When using the TypeScript for...of loop, TSLint throws a typedef error expecting the first variable to have a type definition, however that is not allowed in TypeScript.

Sample:

let names: string[] = [...]
for (let name in names) {
    ...
}

TSLint wants name to have a typedef, however that is not allowed in TypeScript.

[adidahiya]

duplicate of #743