removed resetting of volume derivatives before output to perform the output

fixed bug in saturation flash: mole equilibrium ratios had still been formulated for old fluid framework
episode end and end of simulation cancel error correction.

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@7899 2fb0f335-1f38-0410-981e-8018bf24f1b0