subgrid_list gets a size method
always use Fem::GlobalRefine to ensure DofManager consistency

Conflicts:
	src/thread_vis.cc
switch to new dune-stuff function interface
fix massweight parent class
[cmake] remove obsolete config.cmake header
refactor ell. homogenizer
more homogenizer refactor
more signedness warnings fixed
fix compile with USE_PETSC_BACKEND enabled

Conflicts:
	src/thread_vis.cc
disentangle homogenizer from fem/msfem code paths
Don't use Fem::BinaryFileIOStream, does not work
[cmake] petsc is optional again, disable headercheck
ups, left my chdir in msfem...
splits newton stuff from rhsassembler
[newton_rhs] forgot to move one method definition
deletes elliptic_hom_fem code path
[rhsassembler] split into sep compile unit, remove never called methods
DON'T USE MAGIC VALUES FOR VARIABLE INIT
remove unused anallytical homogenzier
more RHS refactoring