Implement pickup/dropoff types for stopTime entity in schedule viewer

[landonreed]

@mattwigway I'm going to take a crack at adding in stopTime pickup/dropoff

Code reference: parseTime function

[landonreed]

@mattwigway Here are my thoughts on this:

1. a keypress event to specify pickup/dropoff for stopTimes would be appropriate (e.g., d and p).
2. cell highlighting (or border) in the HTML renderer function based on time pickup / dropoff type (right now this is just a placeholder conditional)
3. The thing I need help with is actually modifying the stopTime entity... I'm not sure how to get the stopTime on the keypress

Any thoughts on this approach?

[landonreed]

OK, I've made some headway. It might not be entirely ready for primetime, but once I get your feedback we can further refine:

1. I now have the keypress working for both d and p
2. the modifyStopTimeType function toggles the stopTime from SCHEDULED to NONE (other options not accounted for presently)
3. the highlighting is now showing yellow for no dropoff, blue for no pickup, and red for no pickup or dropoff (these need to be refined for style/legibility and other combinations. Maybe the styling should follow another pattern, e.g., range of background colors for dropoff values and a range of border colors for pickup values.