interCondensatingEvaporatingFoam mishandles heat conduction

Hey all,

I've tested interCondensatingEvaporatingFoam and found a pretty significant issue. If one takes a stagnant container with an initial condition of separated vapor and liquid phases, it appears that a strong temperature sink appears at the liquid/vapor interface. I noticed that this is because heat conduction is treated as laplacian(k/cp,e), which is wrong since e is discontinuous across the boundary due to the latent heat difference, and taking its gradient gives weird results.

I believe I can fix this issue, do I just submit a PR once it works?