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

test/schur_complex.cpp

@@ -79,7 +79,7 @@ template<typename MatrixType> void schur(int size = MatrixType::ColsAtCompileTim
   }
 }
 
-void test_schur_complex()
+EIGEN_DECLARE_TEST(schur_complex)
 {
   CALL_SUBTEST_1(( schur<Matrix4cd>() ));
   CALL_SUBTEST_2(( schur<MatrixXcf>(internal::random<int>(1,EIGEN_TEST_MAX_SIZE/4)) ));