ENH: add IOobjectList::findObject() method

- naming similar to objectRegistry, with unambiguous resolution.
  The lookup() methods have different return types depending on the
  calling parameter.

STYLE: use IOobjectListTemplates.C for implementations

- previously included as local definition within IOobjectList.C,
  but will be adding more templated methods soon.

- adjust parameters (eg, matchName instead of matcher) to show their
  function

ENH: handle objectRegistry::names<void>(...)

- this is equivalent to no Type restriction, and can be used when
  filtering names. Eg,

     obr.names<void>(wordRe..);

applications/utilities/postProcessing/lumped/lumpedPointForces/lumpedPointForces.C

@@ -141,7 +141,7 @@ int main(int argc, char *argv[])
 
         // Pressure field
         autoPtr<volScalarField> pField
-            = loadField<volScalarField>(mesh, objects.lookup("p"));
+            = loadField<volScalarField>(mesh, objects.findObject("p"));
 
         // The forces per zone
         if (movement().forcesAndMoments(mesh, forces, moments))