I think it wont hurt in other usecases

This reverts commit 5d552579cc0467c80ca1d644ede91cd1fb56b371.

Conflicts:

	dune/stuff/function/expression.hh

Reverted because CMake hard fails if Eigen's not present:
CMake Error at cmake/FindEigen3.cmake:33 (file):
  file Internal CMake error when trying to open file:
  ABSPATH/multiscale-super/dune-stuff/../local/include/eigen3/Eigen/src/Core/util/Macros.h
  for reading.

you can now use HAS_STD_BEGIN_END and HAS_LAMBDA_FUNCTIONS to wrap code

testing with ctest also works

which is so much simpler than the autofools setup it's not even funny