Linear Shallow Water Equations - Variable Bottom Topography

[fluidnumerics-joe]

Is your feature request related to a problem? Please describe. SELF Users have requested to add variable bottom topography to the linear shallow water solver so that linear topographic Rossby waves can be modeled.

Describe the solution you'd like

• Change the SELF_LinearShallowWater % H attribute to be a TYPE(MappedScalar2D).
• Add methods for setting the bottom topography (the H attribute) from string, feq-parse equation, or constant REAL(prec) value.
• Adjust the Source, Flux, and RiemannSolver methods to use variable bottom topography
• Add a requiredDiagnostics field and set the gravity wave speed to iVar=1 index.

[fluidnumerics-joe]

Pull Request #39 resolves this issue