Lily/add atom

Add https://atom.io/packages/api-blueprint-preview to http://apiblueprint.org/ in the list of tools. 

Note that the image-size() failed to compile without giving the full path 
@kuba-kubula how do you normally compile it? I did it manually (stylus < assets/apiblueprint.styl -I ./node_modules/nib/lib/ > assets/apiblueprint.css) and couldn't get it to work.