General - Migrate Ethlance Tests from Travis to CircleCI

[benzap]

Travis has been causing issues with testing, since it appears to lack certain criteria to reproduce builds from their end.

CircleCI uses self-contained docker images in a fashion that makes tests reproducible from any user's machine, making it suitable as a build tool, and makes testing and deployments more seamless.

[benzap]

@fbielejec showed interest in migrating to CircleCI

[madis]

Done