Use david DM to check dependency state

Have a look at : https://david-dm.org/
It check if your project dependencies are up to date and give you an image.
Work only for "node" project
Monitor devDependencies

Use the david-dm devDependencies badge as those are the only dependencies that we use
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Update npm modules + grunt task for hologram
Add assets for the styleguide and configuration

doc_assets: template for the styleguide (how to wrapp a code example
block)
styleguide_assets: assets that we can use in the doc
Styleguide documentation for the colors variable. WIP
Git ignore public/

We don't want to version control the public dir as we will publish it
every time we push
Update the development section of the doumentation
Added logotype as asset for the Style Guide
Start a webserver via grunt
Untrack generated css files
Use scss file for styling the styleguide
Fix css file to use in the styleguide
Documentation for the colors
Cleanup folders
Livereload
Removed unused elements
Style guide color variable updates

- Make it possible to have a common background for all colors descriptions