Added a solution of the measles problem in the SIR lab using scikits.bvp_solver.
Cleaned up the first lab on the pseudospectral method, and added a plot.
Merge branch 'develop' into spectral

Merging first pseudospectral lab.
Add nonzeroDirichlet.pdf
Commented out description of dopri5. Added an example solving a BVP using bvp_solver, and described how to separate the boundary conditions in the measles problem.
Merge branch 'develop' into bvp_solver

Merge work on SIR lab
Merge pull request #584 from joshualy/bvp_solver

BVP solver
Merge pull request #583 from joshualy/spectral

Adding an ode lab using the pseudospectral method