remove spurious array declaration and fix timestep
Change "convergence" to "stability"

Ugh. How didn't I notice this mixup before?
Add CFL condition figure
Embed CFL figure and make text more precise
LaTeX typo
fix typo in jsanimation explanation text
Add four stencil figures
typo fix
Merge pull request #5 from numerical-mooc/master

Updating my fork version from numerical-mooc