ENH: Initial integration of IHCantrabria wave functionality

- Wave models significantly restructured and refactored into a hierarchy of run-time selecatable models
- Gravity no longer hard-coded
- Ability to use any direction as the gravity direction
- Boundary conditions simplified and take reference to the wave model
  - removes a lot of code duplication and new code is ~30% faster
- Removed unused functions

Requires further testing
- Restart behaviour needs to be addressed

integration/OpenCFD/code/Allwclean

@@ -0,0 +1,5 @@
+#!/bin/sh
+cd ${0%/*} || exit 1    # run from this directory
+
+wclean libso waveModel
+wclean libso waveBCs