Updates Car.java with implementation of toString method. The failing canDoToString test in CarTest.java now passes.
Updates CarTest.java with canDecelerate test. Test Failed.
Updates Car.java with decelerate method. CarTest.java test canDecelerate now passes.
Updates CarTest.java with cannotDecelerateBeyondZero test. Test Failed.
Updates CarTest.java cannotDecelerateBeyondZero test. Test passes. No modifications to Car.java required.
Updates Car.java and CarTest.java tab characters to spaces.