Allow the 'results' Collection method to also return brains 

QueryBuilder takes an additional keyword parameter **brains** to let it return a list of brains instead of an IContentListing object.

See here:
https://github.com/plone/plone.app.querystring/blob/master/plone/app/querystring/querybuilder.py#L37

I've added this keyword parameter to the Collection's **results** method so that it too can return brains.

Additionally I pinned pygments to 1.6 to fix a pinning error while running buildout.