improvements to neighborhood pages

[thfield]

for neighborhood 'show.html' pages: Goal: provide a brief overview about a neighborhood with the following content:

• [ ] Visual of neighborhood map w/ routes specific to selected neighborhood
• [x] List of routes associated w/ neighborhood
• [x] Description of neighborhood
• [ ] List of connecting neighborhoods

Pieces of this content could be used as a 'neighborhood snapshot' on the homepage

[thfield]

need to complete #43 for bullet point 2: List of routes associated w/ neighborhood

[thfield]

• [ ] JS files should be cleaned up and combined into single script shared between Bikeroutes and Neighborhoods index.html pages.
• [ ] Bikeroutes and Neighborhoods show.html pages should be using mapbox maps to show more detailed views.

[thfield]

(just for future reference, #43 completed via script that lives in lib/assets)