adding some basic styles for DL lists

[alpower]

Adding some basic classed styles for DL lists - list, stacked, inline for https://github.com/dabapps/roe/issues/215

• [x] added to budo example
• [x] added less variables
• [x] add styleguidist app examples
• [x] add styleguidist less variable examples

@dl-label-width: @label-width;
@dl-label-color: @grey-medium;