fix(build): update dependency

Gruntfile.js was using syntax unknown to the package version used.
So I update it npm and bower package
style(layout): reorganize usemin block to be more consistent
fix(screenshot): solve usemin generation

I had some conflicting name and misused the usemin block
fix(grunt): add missing assets to dist/ directory

* JSON ;
* JS ;
* HBS ;
* images/assets/**.png.