Adding optional build of the thermo tpe per reaction. This thermo is not necessary for solid reactions.

NOTE: in Reaction.C constructors bool initReactionThermo is used by solidReaction where there is no
need of setting a lhs - rhs thermo type for each reaction. This is needed for mechanism with reversible reactions

tutorials/combustion/fireFoam/LES/simplePMMApanel/0/panelRegion/qr

@@ -11,7 +11,7 @@ FoamFile
     format      ascii;
     class       volScalarField;
     location    "0";
-    object      Qr;
+    object      qr;
 }
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 

tutorials/combustion/fireFoam/LES/simplePMMApanel/constant/pyrolysisZones

@@ -29,7 +29,7 @@ FoamFile
 
             filmCoupled     false;
 
-            radFluxName     Qr;
+            qrHSource       on;
 
             minimumDelta    1e-6;
 

tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/constant/chemistryProperties

@@ -33,7 +33,7 @@ EulerImplicitCoeffs
 
 odeCoeffs
 {
-    solver          Rosenbrock43;
+    solver          Rosenbrock34;
     absTol          1e-12;
     relTol          0.01;
 }

tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/constant/reactions

@@ -1,3 +1,12 @@
+elements
+(
+O
+C
+H
+N
+);
+
+
 species
 (
     O2

tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/constant/thermo.compressibleGas

@@ -21,6 +21,10 @@ O2
     {
         molWeight       31.9988;
     }
+    elements
+    {
+        O       2;
+    }
     thermodynamics
     {
         Tlow            200;
@@ -42,6 +46,11 @@ H2O
     {
         molWeight       18.0153;
     }
+    elements
+    {
+        O       1;
+        H       2;
+    }
     thermodynamics
     {
         Tlow            200;
@@ -63,6 +72,11 @@ CH4
     {
         molWeight       16.0428;
     }
+    elements
+    {
+        C       1;
+        H       4;
+    }
     thermodynamics
     {
         Tlow            200;
@@ -84,6 +98,11 @@ CO2
     {
         molWeight       44.01;
     }
+    elements
+    {
+        C       1;
+        O       2;
+    }
     thermodynamics
     {
         Tlow            200;
@@ -105,6 +124,10 @@ N2
     {
         molWeight       28.0134;
     }
+    elements
+    {
+        N       2;
+    }
     thermodynamics
     {
         Tlow            200;