Advection-diffusion: save Firedrake/PyOP2 versions
Advection-diffusion: switch to unit square mesh
Firedrake Poisson: store COFFEE config and version info as metadata
Firedrake Poisson: enable COFFEE ap optimisation
qsub: run problem once before starting benchmark
Firedrake advection-diffusion: enable COFFEE ap optimisation
Cahn-Hilliard: switch size from parameter to series
Firedrake Cahn-Hilliard: enable COFFEE licm + ap