Deleting simple Cahn Hilliard example. First trial Flory Huggins with many...

Deleting simple Cahn Hilliard example. First trial Flory Huggins with many terms (simple substitution of y=laplace(phi_tot) instead of the entire chemical potential) still doesn't work properply. For now continuing with amended Cahn Hilliard which accounts for Flory Huggins free energy. The other Flory Huggins code probably has a coding/fenics issue I don't see.