For bit-exact restarts, the ice velocity components should be stored in the initial/restart files on the CG grid.

Required steps:

• The CGDynamicsKernel class provides a setCGArray function to support passing CG data directly to the appropriate dynamics kernel setData will accept all ModelArray::Types.
• Add more intelligence to ma2cg to deal with H, DG and CG types, rather than assuming everything is H.
• Dynamics implementations (BBMDynamics & MEVPDynamics) should return the CG arrays as part of the return data for getDataPrognostic().

The reading and writing of CG arrays by ParaGridIO should already be supported, but this needs to be checked.