Global namespace or prefix (feature request)

[Jeff Pelletier]

Its fairly common with design tokens to use a namespace or prefix for all tokens. For example:

$ns-text-color: #000

where ns- is the namespace. The only way to do this without hacking Theo's core is to manually prepend all variables in yml files with the namespace. Would be great if Theo supported namespacing for all formats from a central location.