inconsistent and unnecessary.
this is purely a cosmetic change, the only exception was a function with
the generic name 'split', which was renamed to splitParam to avoid confusion.
Note that this patch does not introduce any real temperature
dependence but only changes the APIs for the viscosity and for the
density related methods. Note that I also don't like the fact that
this requires so many changes to so many files, but with the current
design of the property classes I cannot see a way to avoid this...
the largest change is that all classes below opm/core/props/pvt take
the PVT region index as an argument, the higher-level ones (i.e.,
BlackoilProps*) take cell indices.
