Feature/promise timeout

[jsconan]

Add a helper that watches a promise and reject it if its duration exceeds the given amount of milliseconds.

promiseTimeout(promise, {timeout: 1000})
    .then(() => {
        // ...
    })
    .catch(err => {
        if (err && err.timeout) {
            // ...
        } else {
            // ...
        }
    });

Unit test:

npm run prepare
npm run test promiseTimeout

[krampstudio]

very nice!