[cleanup] Replace dune_static_assert by C++11's static_assert.

dune/common/densematrix.hh

dune/common/documentation.hh

dune/common/dynmatrix.hh

dune/common/fmatrix.hh

dune/common/forloop.hh

dune/common/fvector.hh

dune/common/gcd.hh

dune/common/hash.hh

dune/common/lcm.hh

dune/common/parallel/remoteindices.hh

dune/common/poolallocator.hh

dune/common/propertymap.hh

dune/common/test/CMakeLists.txt

dune/common/test/Makefile.am

dune/common/test/fvectortest.cc

dune/common/test/gcdlcmtest.cc

dune/common/test/static_assert_test.cc

dune/common/test/static_assert_test_fail.cc

dune/common/test/tuplestest.cc

dune/common/test/tupleutilitytest.cc