Splitting gulp tasks into small files

I use use google web starter kit in big projects and very often the `gulpfile.js` gets really large while trying to automate as much as possible specific tasks. 

So I end up separating the Gulpfile into small files each file is responsible of it's own task only.
Nice job.
Personnaly, I prefer keep the `tasks` folder rather than using a new folder called `gulp` at the root level.