added a rake run task to run the awhole app on hardcoded inputs, also changed y value back to 5 which was the provided data for the challenge
specified array position instead of using shift for parsing coordinates, so #land_rovers is not dependent on #parse_commands being run first
edited README
extracted rover#turn_left, #turn_right, #moves_forward into different direction subclasses using polymorphism
extracted moves forward to their direction sub classes
Merge pull request #6 from christophwong/refactor

Refactor