ENH: boundBox 'reduce' method (related to #196)

reduce()
- parallel reduction of min/max values.
  Reduces coding for the callers.

  Eg,
      bb.reduce();

  instead of the previous method:
      reduce(bb.min(), minOp<point>());
      reduce(bb.max(), maxOp<point>());

STYLE:

- use initializer list for creating static content
- use point::min/point::max when defining standard boxes

applications/test/boundBox/Test-boundBox.C

@@ -60,6 +60,18 @@ int main(int argc, char *argv[])
     Info<<"boundBox faces: " << boundBox::faces << endl;
     Info<<"hex faces: " << hex.modelFaces() << endl;
 
+    boundBox bb = boundBox::greatBox;
+    Info<<"great box: " << bb << endl;
+
+    if (Pstream::parRun())
+    {
+        bb = cube(Pstream::myProcNo(), 1.1);
+        Pout<<"box: " << bb << endl;
+
+        bb.reduce();
+        Pout<<"reduced: " << bb << endl;
+    }
+
     return 0;
 }