Implement new sliding screen-based layout

To better meet mobile expectations, this commit implements a new
layout based on screens. The first screen is the form and location
button. The second screen is the map and directions.

This also includes new background, color scheme and typography.

TODO: working back button
Make back button work
Fix non-working results show action
Add location information placeholders to layout
Style streetview and location data for mobile
Styling fixes and refinements for mobile view
add directions link

This'll need a new location/styling once the map is properly displayed. iOS map links direction taken from https://developer.apple.com/library/ios/featuredarticles/iPhoneURLScheme_Reference/MapLinks/MapLinks.html#//apple_ref/doc/uid/TP40007899-CH5-SW1.
More small styling fixes and refinements
Changes to .scss for web layout, also added small version of logo for web and mobile.
Merge pull request #15 from carpeliam/screens

add directions link
Merge pull request #16 from WheresHJ/screens

Changes to .scss for web layout, also added small version of logo for web and mobile.
Merge branch 'master' into screens
Merge branch 'screens' of github.com:codeforboston/cambridge_voting_locations into screens
Add footer and style location link
Check in CfB logo
Add up arrow icon
Fixes for horizontal scrolling - theoretically
add fail case implementation for geolocation
Adds buttons to header element
Minor fix to direction style