move docker images to cloudmesh organization on docker hub

[badmutex]

@laszewsk current the docker build images are being published to my namespace on dockerhub: https://hub.docker.com/u/badi/

We need to coordinate to switch them to be under the cloudmesh organization instead.

TODO

• add user badi to the cloudmesh organization: https://hub.docker.com/u/cloudmesh/
• fix image namespace in makefile
• fix image namespace in .travis.yml