make the simulator the top-level class responsible for restart files

so far, responsibility was split between the problem, the simulator
and the start() method. Historically, this emerged because the
simulator used to be responsible for just time management.
don't use ANSI escape sequences when the output goes to a log file

In that case, instead of clearing the rest of the line, start a new
one...
Eclipse output: add some valgrind checks for definedness
EclipseSolution: make sure that attached keywords are not accidentally deleted
ECL problem: fix the episode handling

now the episodes seem to match the report steps...
add a base class for primary variables

... instead of using Dune::FieldVector directly. This is required to
make all primary variable classes exhibit a checkDefined() method
which in turn is necessary because the compiler adds alignment bytes
for classes which have additional attributes which result in
Valgrind::CheckDefined(priVars) producing a false positive warning...
black-oil model: make it use primary switching

that approach is more similar to the one used by eclipse and hopefully
it is also more stable...
blackoil model test: update reference solution

For some reason, it changed because of the transition to the primary
variable switching approach. Because I trust the new result more than
the old, let's make this the new reference solution.