Previously, it got passed the weights only needed for CPR.
Additionally those were passed with the parameter tree to the
update method and constructor.
Now the CPR constructor gets a function to use for recalculating
the weights and the property is not changed. Unfortunately this
means that the preconditioner creators of the factory get another
parameter.
Also use it in flow_blackoil_dunecpr.cpp. Adds new command-line parameter,
--linear-solver-configuration-json-file, to read linear solver config from
JSON-format file at runtime.
