[WIP] Feature/git helpers

Feature branch for:
- Git helpers
- "Gulp" deploy command (deploy CSS/JS files, which are compiled locally, to the target server)

More infos:
https://divio-ch.atlassian.net/browse/TECH-1
we currently need compass compile for the css preprocessing and gulp for javascript (and the rest) the goal would be to have only "gulp" at some point.