Updated topics list

URL to be checked
Changed basic colors
Deleted sidebar from main content
Updated content
Uploaded news image
Uploaded banner background cover

Will be replaced with dynamic datavisualization
Added banner background cover
Added sidebar background on homepage banner
Created a class for banner background cover
Changed basic button style
Added btn-big class
Added Century Gothic
Modified navbar-text style
Changed form elements styel
Added banner call to action style and position
Modified banner sidebar style
Minor fix
Merge branch 'new-design' of https://github.com/etalab/etalab-assets into new-design

Conflicts:
	demo/images