* update electron to 1.8.2
release notes: https://github.com/electron/electron/releases/tag/v1.8.2
* change yarn installation on travis
travis detects yarn lockfiles and automatically uses yarn in that case so no need to install it
* yarn is preinstalled on circleci
* Add CircleCI Badge
* Fix typo
* Replace yarn by npm
* Replace yarn by npm
* Always generate the artifacts
* Use yarn for everything
* Also pin dependencies with Yarn
* Install yarn
* Adjusted config
* Only copy ZIP file
* Only build our branches
* Prevent Travis from building on macOS