Updates made to heat flow lab.
Merge branch 'develop' into heat_flow

Merge with develop
Modified first two finite difference labs.
Added several graphs to heat flow lab.
Minor change here.
Merge branch 'develop' into heat_flow

Merging with develop
Merge pull request #605 from joshualy/heat_flow

Heat flow
Beginnings of the Lorenz equations and chaos lab.
Added some basic exposition on the Lorenz equations.
Also added a few examples of how to use animation in Mayavi.
Finished the section on animations in the Lorenz lab.
Added short section on Lyapunov Exponents.
Added a helpful note to the Lyapunov exponent problem in the chaos lab.
Added plots to the chaos lab.
Update the plot for the problem with Lyapunov exponents.
Added solutions for the chaos lab.
Updated problems in chaos lab to better match the desired solutions.
Updated the lyapunov exponent plot to match the plot generated using the
parameters from the solutions.
Small code formatting fix.
Merge pull request #607 from insertinterestingnamehere/lorenz

Lorenz Equations and Chaos