updated specs to use spec_helper instead of rails_helper
updated contributing.md with new programmers
Guardfile clean
added expect syntax to spec helper
added time_in_minutes to TransportMode::Base. tested for :walking and :driving
added bicycle test for getting time in minutes
added test for getting transit time in minutes
solved issue with transit time (requires departure_time in request)
Merge pull request #22 from CodeforAustralia/feature/7-route-returns-time

Feature/7 route returns time