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/array_replicate.cpp

@@ -68,7 +68,7 @@ template<typename MatrixType> void replicate(const MatrixType& m)
   VERIFY_IS_APPROX(vx1, v1.colwise().replicate(f2));
 }
 
-void test_array_replicate()
+EIGEN_DECLARE_TEST(array_replicate)
 {
   for(int i = 0; i < g_repeat; i++) {
     CALL_SUBTEST_1( replicate(Matrix<float, 1, 1>()) );