Said no-one ever.

Use max-height so very small logos will not be scaled up.

This might cause random failures as the draft files are being accessed by other user

Even if there is no navbar - if there is a pageheaderbutton we need to
show it (E.g. Customise this page on dashboard).

Also added missing advanced and required form symbols.

Center logo / site name.
Add padding to logo / site name.
Serve retina images and resize with css.
Add a line under the logo / site name.
Don't show site name if there is a logo.
Obey nonavbar option in core_renderer.

Dont create duplicate blocks 'requiredbytheme' for any reason.

Strings should always be escaped in templates not before