[Whitespace] Clean up formatting of cmake/modules/Makefile.am
[Buildsystem] Add new test for std::initializer_list

This patch adds a new test that defines HAVE_INITIALIZER_LIST if the
corresponding C++11 feature is found. The test is implemented for both
autotools and CMake.

It also adds a number of missing files to m4/CMakeLists.txt and cleans
up the whitespace in that file.
[CMake] Fix newly added test FindCXXInitializerList.cmake.

Fix some problems with the test and clean up formatting.
Merge branch 'feature/initializer-list-test'

Add a new test for std::initializer_list. Thanks to Christoph for fixing
the CMake side of things!

* feature/initializer-list-test:
  [CMake] Fix newly added test FindCXXInitializerList.cmake.
  [Buildsystem] Add new test for std::initializer_list
  [Whitespace] Clean up formatting of cmake/modules/Makefile.am