[x] Enable multifield output for PN and MN Solver
[x] Enable multifield output for other solvers ==> Still open!
[ ] Refactor Screen output ==> Still open
[x] Create Option that handles what so save in vtk output
[ ] Create CSV History Output of important scalar outputs (are there any?) ==> Still open
[x] Restructure solver class + abstract as much as possible
[x] Create default values for SCREEN_OUTPUT
==> Regarding output:
There is now a option called SCREEN_OUTPUT = (ITER, RMS_FLUX,MASS) where one can specify output fields, which the solver should write to screen.
There is now a option called HISTORY_OUTPUT = (ITER, RMS_FLUX,MASS) where one can specify output fields, which the solver should write to a csv file.
The output fields have to be checked at config.cpp : SetPostprocessing, if they contain groups that are not suited for the solver, i.e. the SNSolver does not have MOMENTS as output. This must be done be the coder!
The solver screen output has been nicely formatted.
Test cases for logger have been added.
Added option LOG_FILE where one can specify a file name for the logger. Default is the date of execution.