Initial group of +cheb files.
Fixed typos and added the no-shadow requirement.
Merge branch 'development' into feature-cheb-package
Bivariate normal distribution added to +cheb.
Introduction of gallery2.
Added gallery.m and did some clean-up of other files.
Improving cheb.gallery
adding the sawtooth polynomial.
re-ordering some code.
adding description for funs{12}.
Merge branch 'development' into feature-cheb-package
Completing work on the cheb.galleries.

- Moved periodic functions to cheb.gallerytrig (whose name we will
  talk about at a meeting).
- Made gallery2 and gallerytrig consistent with the way gallery works.
- Made consistent all documentation.

However, gallerytrig only has one lonely member right now.
More functions need to be added.
Agreed changes to cheb.x and cheb.t, also cleanup.

- Removed cheb.t as we agreed in a meeting a while back.
- cheb.x now returns the chebfun instead of assigning it.
- Renamed normal2d to normal2.
- Improved documentation to a couple of files.
Modifying +cheb README.

- Removing the rule that names of +cheb functions cannot shadow
  names of existing MATLAB functions (we already do this with the
  gallery anyway).
- Removing the blurb at the end about how to add new code. Perhaps
  will put it back after some discussion.
Added 3 functions to gallerytrig.
Adding the "complicated function" from the 100-digit challenge.
Updated gallery to work with string inputs. Needs documentation.
Finished documentation for the gallery.
Added bump function and Blasius function, and alphabetized.
Completed gallery2.