Added tests for Week 4.
Removed front impact controller from demo and updated the second test to check if the robot has moved at all.
Updated manual for Week 4.
Merged manual from coursera-sp14 branch.
Merge branch 'coursera-week-4' of github.com:jdelacroix/simiam into coursera-week-4
Merge branch 'coursera-sp14' of github.com:jdelacroix/simiam into coursera-week-4
Fixed manual conflicts.