cross-ci/index.d.ts

`cross-ci` standardizes environment variables for CI. For example, your can simply use `BUILD_BRANCH` variable in all CI runners instead of `CIRCLE_BRANCH` in CircleCI or `TRAVIS_PULL_REQUEST_BRANCH` in Travis.

import createVars = require('./lib/createVars');
export { createVars };
export declare const vars: createVars.ICrossCIVars;