Fixed another typo.
Left out a couple of key steps in the description of the Cepstral
coefficients, so I added them in.
Fixed yet another mistake.
Merge pull request #388 from abefrandsen/cepstrum

Cepstrum
modify profiling lab

Add to a list of suggested labs to profile and optimize.

Also fixed a typo in one of the examples.
Merge pull request #389 from ayr0/profile

modify profiling lab
Fixed a formatting issue in Volume 3.
Merge pull request #390 from insertinterestingnamehere/v3_hotfix

Fixed a formatting issue in Volume 3.