Change request fromTime/toTime to align more with user needs and algorithm possibillites.

[t2gran]

It might be better to change the request parameters from fromTime, toTime, maxTravelTime and arriveBy to:

New request params - replacing the above:

• earliestDepartureTime
• latestDepartureTime
• earliestArrivalTime
• latestArrivalTime

At least one of these is required.

´Tuning` params:

• defaultSearchTimeWindow (DTW)

We think this will make it possible to run time window search in parallell, e.g. Find the best options for the next 3 days, by splitting the search in 3 hour windows and merging the result with the same pareto-criterias.

Relates to #13 ArriveBy implementation.

The maxTravelTime is suboptimal because it assume the end user or system actually know the expected travel time.

[t2gran]

Something similar is implemented:

• earliestDepartureTime
• latestArrivalTime
• searchWindowInSeconds
• arriveBy