Merge branch 'doself2-vectorisation' into 'master'

Pad properties with sensible values to prevent floating point exceptions.

Try again. I have ran the test that fails in the Jenkins script 3 or 4 times and it runs fine.

See merge request !415

src/runner_doiact_vec.c

@@ -702,6 +702,9 @@ __attribute__((always_inline)) INLINE void runner_doself2_force_vec(
         cell_cache->h[i] = 1.f;
         cell_cache->rho[i] = 1.f;
         cell_cache->grad_h[i] = 1.f;
+        cell_cache->pOrho2[i] = 1.f;
+        cell_cache->balsara[i] = 1.f;
+        cell_cache->soundspeed[i] = 1.f;
       }
     }