Feature/driver adaptive

This MR introduces a driver which uses an adaptive polynomial order procedure for 2D and 3DH1D expansions.

I only tested it for the incompressible solver, but I suppose it might work with other solvers as well. Extending it to 3D should be simple, but I did not attempt that since the incompressible solver does not support variable order in 3D yet.

A bug in ExtractCoeffsToCoeffs is also fixed by this branch.