Route updates

[doublestranded]

closes #268

on precog: https://precog.mapzen.com/transitland/www-transit-land/route-updates/documentation/datastore/routes-and-route-stop-patterns.html#vehicle_types

[kkowalsky]

The Vehicle Types section is linked, but doesn't have a path... Is that intentional? Also vehicle types 1702 and 405 are the best.

add 'a' before 'Douglas-Peucker algorithm' and link to a page (for those of us who don't know what that is).

In the Distance calculation heuristic algorithm section, 💯 for explaining the algorithm behind stop patterns, that's immensely useful. There's a spelling error after that paragraph, "Transitland logs inaccuraties" <-- should be inaccuracies

[kkowalsky]

After those two spelling checks, you're all set by the docs team 😄

[drewda]

This is looking good, @doublestranded. And thanks for your close read, @kkowalsky.

A few improvements we should do before merging:

• in the vehicle types table, add in the basic vehicle types: https://github.com/transitland/gtfs/blob/master/lib/gtfs/route.rb#L15-L22
• in the vehicle types table, also mention the strings that Datastore API takes in queries (e.g., railway_service instead of `1001) and link to example queries
• replace mention of RSP is_generated with the new geometry_source enum being added in Utilize shape dist traveled transitland-datastore#994

I can work on the first two of those items.

[doublestranded]

Thanks @kkowalsky and @drewda! Good eyes. I've made the edits (using the Douglas-Peucker Wikipedia page for stability. Plus it has a good graphic). Thanks for making the vehicle types section more complete @drewda !