Changed vp refs to vpf - shorthand for viperfish
Removed utils class

Not necessary just yet
Added logic to handle category requests

At the moment there are a number of assumptions being made about the parameters being passed in with the GET request
Got the category route collecting the category json

Required changes to the category json files in the git repo - currently only git and code categories have category json files, so typography and soap categories won't work
Added nav links to navigate to categories

Only git and code work because soap and typography don't have correct json files and the routing code can't handle errors in the json (or, indeed, missing json files)