Lab2

Here are my suggested edits to lab2. After talking to the TAs and students in the class, we decided that timing things was too complicated for a beginning lab (not to mention that it isn't part of this lab's objective), so we removed those problems. The plan is to include timing in the profiling lab.
It would be really nice to have the online documentation listed here. Then it would be easy to find how to implement each of these functions. Some have more capabilities than is listed in the following table.