CI: migrate to src-d/ci and add release profile

[bzz]

https://github.com/src-d/ci/tree/v1 is a standard build system for applications that does all the things current make file does (build in docker, etc).

TODOs

• replace current make file with a new one, based on src-d/ci
• add release profile to .travis.yml for DockerHub push as well as binary built on tag