go back to incrementing the current simulation time first, then calling EclipseWriter::writeSolution()

for this not to trigger an assertation after the last time step, the
changes of OPM/opm-parser#141 are required.
Merge pull request #98 from andlaus/reverse_increment_write_order_again

go back to incrementing the current simulation time first, then calling EclipseWriter::writeSolution()