docs(css): Install styledocco

Addresses #289 - this puts in the beginnings of styledocco, which can be run by typing in grunt styleguide right after grunt server is run. Subsequent pushes will feature non angular mark-up in the LESS comments so it will be seen in the styledocco documentation.

cc: @flazz 
If we can, I think it's better to use an existing solution that's been fully tested and already has a lot of work put in to it. 

One of the issues with this file is that it has a hard-coded path to `node_modules`, which will cause it to break if that folder name changes (same goes for the LESS path in the options file). 

I've taken a quick look through the grunt-styleguide repo and they don't use the hard-coded path. Can you look more into grunt-styleguide as a solution, then we can look at converting encore-ui-template over if it works out?