Implement PyOptSparse and SNOPT

[johnjasa]

• First need to understand how dolfin interfaces with the Scipy optimizer
• Can then either replace that with PyOptSparse or we can use dolfin to create a functional and adjoint method call, which we then feed to PyOptSparse manually
• Will probably need to purposefully think about the user interface that reduces exposure to PyOptSparse, and that might be its own issue

[johnjasa]

Completed via #26