Major Docker refactor - Githubissues

python 2 and python 3 images (make rep-image2, make rep-image3)
python 2 version is built on circleCI
- tested that jupyter returns page on starting daemon (done on travis)
- running rep tests inside a container (make run-tests)
decreased size of docker (2.2GB instead of > 3 GB), but there is still room for improvement
corrected registering of kernel in the image
one-step building
separate conda-files for python 2 & 3 generated by script
added StopWatch in utils
deleted usage of TRAVIS variables in scripts
improved scripts for building / starting containers
TODO
test python 3 image on CI and make separate tag for publishing
check everware compatibility

yandex / rep