rename Robot#getDistance() => Robot#getFrontDistance()
rename DistSensor#getDistance() => DistSensor#getFrontDistance()
add getter for side distance in Robot class
add getter for side distance in VirtualDistSensor class
remove ineffective test : DistanceSensorTest
fix to use CppUMock in MockDistSensor class
fix to change rotate direction with side distance
Merge pull request #20 from cad-san/fix-to-change-rotate-direction

fix to change direction of rotation