ENH: raw format with optional output for face area normals (#2003)

- the raw surface writer simply outputs x/y/z and field values.
  This additional flag allows recovery of some geometric information.

- optional user-specified output precision

Example,
```
formatOptions
{
    raw
    {
        normal      yes;
        precision   10;
    }
}
```

tutorials/compressible/rhoSimpleFoam/squareBend/system/samplingDebug

@@ -16,6 +16,7 @@ debug
     interpolationScheme cellPoint;
     surfaceFormat ensight;
     // surfaceFormat vtk;
+    // surfaceFormat raw;
 
     formatOptions
     {
@@ -24,6 +25,11 @@ debug
             collateTimes  true;
             // collateTimes  false;
         }
+        raw
+        {
+            normal  true;
+            precision 8;
+        }
     }
 
     _plane