[Cs3] example final, optional lab

[Mikhail Nesterenko]

CS3 students,

I added an example final to the course's webpage for those who are
curious. Note that this one is slightly easier than the current
exam. For example, do not expect softball questions like the 8th to
appear on the actual exam.

Also, I added the 14th lab. This lab is optional. No credit will be
given for submitting it. However, you are strongly encouraged to
code and submit it so that it could be graded and you can get
experience working on the material on that lab. This material will be
on the exam.

The 14 lab is due together with the 13th. If you are submitting the
14th lab for grading, notify your lab instructor.

Thanks,
-- 
Mikhail