fix solution for binary_gray

I'm not sure what binary_gray was doing, but I don't think it was doing
it right.  It should work now as intended.

Also fixed spelling of Gray.
Redid examples in first vectorization lab.
Added a new plot to the vectorization lab.
Deleted old plot for vectorization lab.
Added vectorization exercises.
Added solutions for new vectorization problems
Added hints to new vectorization problems.
Added another one-line problem to the vectorization lab.
Some code formatting fixes.
Use proper logscale for plot in vectorization lab.
Added missing pdf for vectorization lab.
Some small edits to the vectorization lab.
Readded Newton Cotes and Barycentric labs.
Also fixed spacing and figures in Newton Cotes lab.
Merge pull request #317 from insertinterestingnamehere/reorder

Readded Newton Cotes and Barycentric labs.
Merge branch 'master' into vect
Redid shuffling problem in vectorization lab.
Some edits to the image editor problem.
Fixed a typo and some spacing.
Merge pull request #315 from insertinterestingnamehere/vect

Vectorization lab edits
Made changes to Lab 5 in volume 1 (complexity and sparse matrices).