New city design

Do not merge yet. 

TODO: 
* [ ] Social icons
* [ ] Event-specific social, calendar, map icons
* [ ] Use mixins where needed (fonts, colors)
* [ ] ~~Decouple navbar from main city template, into city layout~~
* [ ] Remove sass nesting
* [ ] Gray letters on gray background (design)
* [ ] Navbar items hover effect
* [ ] Jade mixin for city communities
* [ ] Image for each community
* [ ] Community titles not perfectly vertically aligned
* [ ] Event title & details trim words to fit
* [ ] Footer
This needs to be configurable per city :/