Extrapolate unsaturated function values as in Eclipse and Mrst
Extend relperm and capilary pressure tables with constant values such
that the derivatives at the endpoints are zero
An initial guess of the surface volume is now computed using the RS
factor in order to compute a more accurate A matrix.
The old extrapolation code for the unsaturated table is no removed
The initBlackoilStateFromDeck is now called only if RS is given in deck
Merge pull request #386 from totto82/propsMRST

Changes to the props in order to  sync with MRST (Eclipse)