* Add circlci, remove .travis.yml. Fixes#1839.
* Fix circleci config
* Add slack notification
* Add circleci status
* Fix config.yml, we don't need separate truffle image and instances.
* Matches oz-sdk node version
* Seems node:10.13 doesn't work for CircleCI either
* Remove npm update in circleci
* CircleCI use package-lock.json as cache key and install only the lock version
* Add back travis.yml
* Rename job build to test
* CircleCI requires that job to be called build instead of test or build_and_test
* Fix the way to run jobs
* Fix CircleCI
* Change back to npm install
* Add workflow and split into tasks
* Add workspace
* Restore cache
* update readme circleci instructions
* make step name more accurate
* Rename package and repository name from docs and scripts
* undo root package rename
* add @openzeppelin/contracts as subpackage with release automation
* synchronize @openzeppelin/contracts version
* remove private field from package.json
* make file patterns absolute
* change wording of a comment
* use a saner version script
