Add arrays of red, green, and orange lines
Add user prompts for starting point and destination
Verification add for Haymarket => red or orange
Add a stop distance counter

* Only works on Red Line
Fix case to all lower
Expand user input to work from all three lines
Large update: New hash of MBTA stops

* Change MBTA data from single array to hash with arrays
* Calculate distances of stops from Park Street
Add Haymarket validation to ask for which line
Add while loop to validate for correct MBTA station