Tidyied up and deleted non-motor related stuff

Deleted all line-following and ultrasonic sensor related lines.
Deleted all manual control of stepper motors
Tried to cut down on extra lines of code where possible
Re-ordered variables and where functions are defined to be ready to add
pilot functions: pilotForward(); pilotBackward(); pilotRotateRight();
pilotRotateLeft(); pilotSwingRight(); pilotSwingLeft();
Use of left and right in these future functions is primarily to increase
readability of code. (as opposed to having to work out whether
rotate(-40); means left or right each time.
Note that this will still be easy to change in the future by writing new
functions rotate() and swing() that use rotateRight and rotateLeft.
Fixed distance measurement settings