[IMP] switch theme height
[to CP on 8.0] Snippet showcase
[to CP on 8.0] add classnames to snippets body

Designers can't properly do their job without them
[to CP on 8.0] Remove mb*, mt* from snippet body's root

Now that classnames are provided to snippets bodies, css should be use
for this purpose, allowing the overloading trough css for themes