Default value for departure_time_window

[rafapereirabr]

Brief description of the problem:

We currently set a a default value of time_window = 1L. In a discussion over r5py, Willen shared a discussion in R5 where Matt mentions that using a 1-minute time window can produce problematic results:

We thought about this, but what you actually want to do is run it for a time window of many minutes, and use the routing from the first minute. Otherwise you can get some weird paths. More here: conveyal/r5#42

Alternative solutions:

1. ideal (following Matt's suggestion): if we could run a short window, say 5 or 10 minutes, and then select the result from the 1st minute.
2. compromise: we could change the default value to a short window, say 5 minutes. This waiy, we would keep the function both performant and in line with the behavior most users would expect.

[rafapereirabr]

Ok. Setting default value to 10 minutes, making consistent the default behavior between r5r and r5py r5py/r5py#292