Get rid of EIGEN_TEST_FUNC, unit tests must now be declared with EIGEN_DECLARE_TEST(mytest) { /* code */ }.

This provide several advantages:
- more flexibility in designing unit tests
- unit tests can be glued to speed up compilation
- unit tests are compiled with same predefined macros, which is a requirement for zapcc

unsupported/test/dgmres.cpp

@@ -24,7 +24,7 @@ template<typename T> void test_dgmres_T()
   //CALL_SUBTEST( check_sparse_square_solving(dgmres_colmajor_ssor)     );
 }
 
-void test_dgmres()
+EIGEN_DECLARE_TEST(dgmres)
 {
   CALL_SUBTEST_1(test_dgmres_T<double>());
   CALL_SUBTEST_2(test_dgmres_T<std::complex<double> >());