[buildsystem] Do not check for initializer list.

The check has moved to dune-common.
Remove autoconf check.
Remove remainders of CMake check.
[Includes] Fix headercheck
[Autotools] Remove tests already done by dune-typetree
[CMake] Clean up CMakeLists.txt in folder test/.
[Tests] Fix construction of InterleavedOrdering in ordering tests

The InterleavedOrdering accepts an initializer lists as constructor
parameter describing the block sizes, but we should only test for that
constructor if initializer_list is actually available. Apart from that,
double-wrap the initializer list to make some compilers happy.
[Documentation] Update list of contributors
Merge remote-tracking branch 'origin/master'

* origin/master:
  Fix headercheck.
  [buildsystem] Do not check for initilizer list.

Conflicts:
	m4/CMakeLists.txt
	m4/Makefile.am
	m4/dune-pdelab.m4