H2O: remove too expensive range checks

when they worked, they were only used in debug mode anyway...
capillary pressure laws: move the M-phase laws one directory up

since they are also generic in the sense that they can depend on
arbitrary quanities expressed by the fluid state, not just
saturations...
blackoil fluid system: rename gasFormationFactor to gasDissolutionFactor

that was a thinko/reado of mine...
fix end of namespace comments

long live python ;)!