Preparing 0.8

@shin- @wking @bacongobbler @noxiouz @lyda

This is the last round of changes for 0.8

There really isn't much to it (commits are rather self-explicit), except adding new relic support.

Please review, and if possible, give a spin to the future 0.8 - simplest way is to build the container - otherwise, be sure to:
```
cd depends/docker-registry-core/
python setup.py develop
cd -
python setup.py develop
```

as registry-core is not on pypi yet.