Grrrrrrrrr!!!!!!!
Right now when you type "grunt" you will have a nice prod website.

HOWEVER if you type "jekyll serve" you will lose everything that was
generated and only the jekyll build will be launched instead.

We need to keep bower, grunt and jekyll commands working together.

So the current proposed solution is NOT working.

The command "jekyll serve" should ALL THE TIME ends with a working
website.

Here is the workflow:
npm install
bower install
grunt prod / watch
jekyll build / serve / serve --watch

We should prevent jekyll to remove the files generated by grunt.
Files that are generated in the templates directory.
Those not modified stay directly there.