Create new chapter on fundamental limits, pulling from loopsyn and robperf

[Richard Murray]

To help shorten the chapter on Frequency Domain Design (Loop Synthesis), we are going to create a new chapter on "Fundamental Limits". This will pull material as described in an e-mail from Karl on 4 June:

New Chapter 14 - Fundamental Limitations
14.1 Design Limits (new intro)
14.2 Bode's Integral Formula (Old Ch 12.7, 5 pages)
14.3 Loop Shaping View (First part of old  Ch 12.6 4 pages)
14.4 Function Theory View (Second part pf p;d Ch12.6  6 pages)
14.5 Pole placement (Old 13.4 7 pages, Example 13.11 should remain in Ch 13)
Exercises

The total length will be about 25 pages, Ch 12 will be reduced to 34, Ch 13 reduced to 28.

[Richard Murray]

Initiated in 9f1df0d and now largely complete.