Couple minor changes to multivariate finite differences lab.
Made a very minor typo correction to the Barycentric interpolation lab.
Couple more corrections to multivariate finite diff lab, and added
some updated solutions to the solutions file.
Added a pdf image to the waveletapps lab.
Merge pull request #406 from abefrandsen/finiteDifference

Finite difference
Added clarifying content to the ImageFilters lab. Updated the solutions
file. Added a plotFigs file and updated the pdfs.
Edited the plotfigs file.
Fixed minor typo in Cython lab.
Merge pull request #410 from abefrandsen/student_edits

Fixed minor typo in Cython lab.
Made some changes to make lab better
Merge pull request #411 from AZaitzeff/NC

Made some changes to make lab better
Merge pull request #409 from abefrandsen/finiteDifference

Finite difference
Fixed a typo in the Chebyshev lab.
Merge pull request #412 from insertinterestingnamehere/cheb

Fixed a typo in the Chebyshev lab.