Add support for piecewise chebfuns. Closes #1037.
Implement Regula Falsi. TODO: Illionois.
Implement Illinois algorithm.
Adding Brent's method.
Edit DOCs.
Fix Brents method.
Make bisection algorithm in chebfun.inv() work for decreasing functions.

This closes #1098.
Documentation and style fixes for @chebfun/inv.m.
Merge branch 'development' of github.com:chebfun/chebfun into fix-chebfun-inv
Merge branch 'fix-chebfun-inv' of github.com:chebfun/chebfun into fix-chebfun-inv
Response to review by AA.