Linear Shallow Water verification

[fluidnumerics-joe]

We now have a set of example programs for the linear shallow water solver that are producing reasonable output. It's time to start looking into a more in-depth verification study. This will involve

• Verifying p-refinement convergence rates (varying polynomial degree) in cases where an analytical solution is known ( a new example may be needed )
• Verifying h-refinement convergence rates (varying element size) in cases where an analytical solution is known ( a new example may be needed )
• Verifying time integrator convergence rates
• Assessing the impacts of double and single precision

In working on this issue, I anticipate that recommendations will be developed for improving SELF. Additionally, the verification study may find issues in the solver implementation that can be concretely defined so they can be addressed.