improved matlib + debug output + exceptions + improved RHS + more quantities

@matlib: removed obsolete viennamini::material library class,
-> using viennamaterials directly now -> improved handling in viennamini

@debug output: improved output helps debugging, especially in device,
simulator and problem classes

@exceptions: added excetipns at vital if/else conditions to further
aid debugging

@RHS: added silicon parameters for tau_n/p and set n1/p1 to the electron and
hole concentrations for the time being

@more quantities: with the poisson dd np problem, instead of using single
values, now using cell-based quantities ->
  VT, mu_n, mu_p, ni, T ..