ENH: improved handling of coordinateSystems

- in continuation of #2565 (rotationCentre for surface output formats)
  it is helpful to also support READ_IF_PRESENT behaviour for the
  'origin' keyword.

  This can be safely used wherever the coordinate system definition
  is embedded within a sub-dictionary scope.

  Eg,
      dict1
      {
          coordinateSystem
          {
              origin (0 0 0);  // now optional here
              rotation ...;
          }
      }

   but remains mandatory if constructed without a sub-dict:

      dict2
      {
          origin (0 0 0);   // still mandatory
          e1  (1 0 0);
          e3  (0 0 1);
      }

   With this change, the "transform" sub-dictionary can written
   more naturally:

       formatOptions
       {
           vtk
           {
               scale 1000;  // m -> mm
               transform
               {
                   rotationCentre  (1 0 0);
                   rotation axisAngle;
                   axis    (0 0 1);
                   angle   -45;
               }
           }
       }

ENH: simplify handling of "coordinateSystem" dictionary lookups

- coordinateSystems::NewIfPresent method for optional entries:

    coordSysPtr_ = coordinateSystem::NewIfPresent(mesh, dict);

  Instead of

    if (dict.found(coordinateSystem::typeName, keyType::LITERAL))
    {
        coordSysPtr_ =
            coordinateSystem::New
            (
                mesh_,
                dict,
                coordinateSystem::typeName
            );
    }
    else
    {
        coordSysPtr_.reset();
    }

ENH: more consistent handling of priorities for binModels, forces (#2598)

- if the dictionaries are overspecified, give a 'coordinateSystem'
  entry a higher prioriy than the 'CofR' shortcuts.

  Was previously slightly inconsistent between the different models.

src/functionObjects/field/binField/binField.H

@@ -68,22 +68,21 @@ Usage
 
         // Conditional optional entries
 
-            // Option-1, i.e. general coordinate system specification
+            // General coordinate system specification
             coordinateSystem
             {
-                type            cartesian;
-                origin          (0 0 0);
+                type        cartesian;
+                origin      (0 0 0);
                 rotation
                 {
-                    type        axes;
-                    e3          (0 0 1);
-                    e1          (1 0 0); // (e1, e2) or (e2, e3) or (e3, e1)
+                    type        ...
+                    ...
                 }
             }
 
-            // Option-2, i.e. the centre of rotation
-            // by inherently using e3=(0 0 1) and e1=(1 0 0)
-            CofR                (0 0 0);
+            // Define the centre of rotation
+            // with implicit directions e1=(1 0 0) and e3=(0 0 1)
+            CofR            (0 0 0);
 
         // Inherited entries
         ...
@@ -102,7 +101,7 @@ Usage
       decomposePatchValues | Flag to output normal and tangential      <!--
                 --> components                          | bool   | no   | false
       cellZones | Names of operand cell zones          | wordRes | no   | -
-      coordinateSystem | Coordinate system specifier      | dict | cndtnl | -
+      coordinateSystem | Coordinate system specifier    | dict | cndtnl | -
       CofR    | Centre of rotation                      | vector | cndtnl | -
     \endtable
 
@@ -117,6 +116,9 @@ Usage
       - \link writeFile.H \endlink
       - \link coordinateSystem.H \endlink
 
+Note
+  - If a \c coordinateSystem entry exists, it is taken in favour of \c CofR.
+
 SourceFiles
     binField.C
 

src/functionObjects/field/binField/binModels/binModel/binModel.C

@@ -77,40 +77,27 @@ void Foam::binModel::setCoordinateSystem
     const word& e1Name
 )
 {
-    coordSysPtr_.clear();
+    point origin(Zero);
 
-    if (dict.found(coordinateSystem::typeName_()))
+    coordSysPtr_ = coordinateSystem::NewIfPresent(dict);
+
+    if (coordSysPtr_)
     {
-        coordSysPtr_ =
-            coordinateSystem::New
-            (
-                mesh_,
-                dict,
-                coordinateSystem::typeName_()
-            );
-
         Info<< "Setting co-ordinate system:" << nl
             << "    - type          : " << coordSysPtr_->name() << nl
             << "    - origin        : " << coordSysPtr_->origin() << nl
             << "    - e3            : " << coordSysPtr_->e3() << nl
             << "    - e1            : " << coordSysPtr_->e1() << endl;
     }
-    else if (dict.found("CofR"))
+    else if (dict.readIfPresent("CofR", origin))
     {
-        const vector origin(dict.get<point>("CofR"));
-
         const vector e3
         (
-            e3Name == word::null
-          ? vector(0, 0, 1)
-          : dict.get<vector>(e3Name)
+            e3Name.empty() ? vector(0, 0, 1) : dict.get<vector>(e3Name)
         );
-
         const vector e1
         (
-            e1Name == word::null
-          ? vector(1, 0, 0)
-          : dict.get<vector>(e1Name)
+            e1Name.empty() ? vector(1, 0, 0) : dict.get<vector>(e1Name)
         );
 
         coordSysPtr_.reset(new coordSystem::cartesian(origin, e3, e1));

src/functionObjects/field/fieldCoordinateSystemTransform/fieldCoordinateSystemTransform.C

@@ -60,7 +60,7 @@ fieldCoordinateSystemTransform
     fieldSet_(mesh_),
     csysPtr_
     (
-        coordinateSystem::New(mesh_, dict, coordinateSystem::typeName_())
+        coordinateSystem::New(mesh_, dict, coordinateSystem::typeName)
     )
 {
     read(dict);

src/functionObjects/field/regionSizeDistribution/regionSizeDistribution.C

@@ -396,20 +396,13 @@ bool Foam::functionObjects::regionSizeDistribution::read(const dictionary& dict)
         dict.subOrEmptyDict("formatOptions").optionalSubDict(setFormat)
     );
 
-    if (dict.found(coordinateSystem::typeName_()))
-    {
-        csysPtr_.reset
-        (
-            coordinateSystem::New(obr_, dict, coordinateSystem::typeName_())
-        );
+    csysPtr_ = coordinateSystem::NewIfPresent(obr_, dict);
 
+    if (csysPtr_)
+    {
         Info<< "Transforming all vectorFields with coordinate system "
             << csysPtr_->name() << endl;
     }
-    else
-    {
-        csysPtr_.clear();
-    }
 
     if (isoPlanes_)
     {