Improved relaxation factors for the new buoyantSimpleFoam solver.

Note the reversal between the p and U factors for compressible flow.

tutorials/heatTransfer/buoyantSimpleFoam/hotRoom/system/fvSolution

@@ -76,9 +76,9 @@ SIMPLE
 relaxationFactors
 {
     rho             1;
-    p               0.3;
-    U               0.7;
-    h               0.1;
+    p               0.7;
+    U               0.2;
+    h               0.7;
     k               0.7;
     epsilon         0.7;
     R               0.7;