WALK + BIKE: add distance to turn instruction

[fpurcell]

In both OTP-UI and OTP-RR, the individual walk instructions lack a distance for how far to walk or bike. A lack of distance in the walk instructions was pointed out as an issue in testing with sight-impaired folks.

Here's a visual of what OTP-UI is currently rendering:

Here's a picture of walk instructions with distance from an older (non OTP-UI) app:

NOTE: the distance information needs to make sense when read aloud by a screen reader (e.g., testing needed to come up with the proper wording, etc...).