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/forward_adolc.cpp

@@ -119,7 +119,7 @@ template<typename Func> void adolc_forward_jacobian(const Func& f)
     VERIFY_IS_APPROX(j, jref);
 }
 
-void test_forward_adolc()
+EIGEN_DECLARE_TEST(forward_adolc)
 {
   adtl::setNumDir(NUMBER_DIRECTIONS);