Add CIRCLE_BRANCH_REGEX environment variable to CI script to allow enabling all CI tests on certain branches. Default to master and release-*

Fix some errors due to newer version of babel. Make sure webpack exits with non-zero exit code if build fails ಠ_ಠ. [ci all]

Disable driver and e2e tests by default (except on master), enable with [ci FEATURE_NAME] (drivers, e2e)