Invoice report for Licences.
Remove commented code
Fix flake8 errors.
Merge branch 'develop' of https://github.com/allegro/ralph_assets into invoice-licence

Conflicts:
	src/ralph_assets/urls.py
	src/ralph_assets/views.py
Fix Flake8 errors
Add missing user in asset save
Fix merge conflict
Better formatting
Better message
Shortest join
Merge pull request #223 from quamilek/invoice-licence

Invoice report for Licences.