Init gulp based assets management
Fix references to previous asset paths
Split frontend asset bundles for frontend and backend
Fix css gulp task
Fix tests + add make command for assets
Update CHANGELOG
Update documentation
Merge pull request #417 from plouc/add_gulp

Add gulp for assets management
Move 'compose' block preview rendering to php
Fix block type label when creating new one
Add missing translation
Add missing reference to main doc TOC tree
Merge pull request #421 from plouc/composer_update

Composer update
Fix javascript compilation error