Update CI settings for faster build / Update package.json

* I updated CI setting files.
  * Adding `sudo: false` enables container-based build on Travis CI.
  * Clones repository *shallowly* for faster download.
  * Caches `node_modules` directory on AppVeyor.
* I updated SPDX license type and license file URL in package.json.
  * The license of this project has been changed from e418be967f952a20f5bf137be7b289e0b859fae1.