Newton convergence and Chebgui in Ch.10

[asgeirbirkis]

As discussed in chebfun/chebfun#951 , Newton convergence isn't particularly well behaved once we get close to the solution, and this is evident from the second last figure of Ch. 10. Once we get that issue resolved, Ch. 10 needs to be reproduced.

Also, the screenshot of CHEBGUI in Ch. 10 is missing the plot figures.