Switch to tabs for indentation

I got drunk, read the coffeescript style guide, and decided to use
spaces. Spaces for indentation is still as bad an idea as it ever were,
and this is not a coffeescript project - it's multilingual, hence using
coffeescript conventions is pointless.
Basic grid with awesome properties

The goals were to make the grid as spacious as possible, while not
compromising many-column layouts and small screen sizes. Works for an
arbitrary number of columns and adjusts horizontal spacing according to
the number of columns and the viewport size.