Added amenities to categories and set university to default category
Set category_name to defaultCategory if none specified
Removed unused code from CategoriesView
Add links between amenities and university
Refactor additionalCollections into a registerAdditionalCollection

Added an event for when additional collections are created to be added
to the map.

MapView also manages a list of "visible" layers. So we know if a
collection has been selected or not.
Pass list of visibleLayers to CategoriesView to check selected items
Updated CategoriesView and template for togglable AdditionalPOIs
Configuration for togglable categories with icons
Merge pull request #14 from ox-it/amenities-categories

Amenities categories