Redid spacing and formatting in the heat flow lab.
Initial editing pass on heat flow lab.
Added a description of how to do animations in Matplotlib.
Added tridiagonal algorithm to the heat flow lab.
Also cleaned up various other miscellaneous things.
Added various hints for implementation.
Fixed Error plot to match problem in Heat flow lab.
Typo fixes.
Merge branch 'master' into heatflow
Merge branch 'master' into heatflow
Merge pull request #616 from insertinterestingnamehere/heatflow

Heatflow