adding files for trigonometric interpolation.
renaming a file.
adding tests for trigBary and interp1.
Merge branch 'development' of https://github.com/chebfun/chebfun into feature-trig-interp
adding references for trig interpolation.
adding a test and some comments for interp1.
fixing a small bug
Merge branch 'feature-trig-interp' into development
Remove some unnecessary whitespace/comments in trigBary.