Move testhydro.sh to examples/ directory because it is just play, not a test (where the answer is known).
Removed englacial storage, as conserved mass, from codes.  But several new FIXMEs, especially related to: (i) move update of Wtil before W update; (ii) fix PISMNullTransport version of updating Wtil; (iii) what exactly *is* our model for pressure in the till pore-water?