Adapt to CMake-based build system.

Specifically,

  - #include <config.h> where appropriate (all .cpp files)
  - Adjust include statements to account for sub-directory locations
    of .hpp files.

tests/test_block.cpp

@@ -17,13 +17,15 @@
   along with OPM.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <config.h>
+
 #if HAVE_DYNAMIC_BOOST_TEST
 #define BOOST_TEST_DYN_LINK
 #endif
 
 #define BOOST_TEST_MODULE AutoDiffBlockTest
 
-#include "AutoDiffBlock.hpp"
+#include <opm/autodiff/AutoDiffBlock.hpp>
 
 #include <boost/test/unit_test.hpp>