ENH: avoid readScalar, readLabel etc from dictionary (#762, #1033)

- use the dictionary 'get' methods instead of readScalar for
  additional checking

     Unchecked:  readScalar(dict.lookup("key"));
     Checked:    dict.get<scalar>("key");

- In templated classes that also inherit from a dictionary, an additional
  'template' keyword will be required. Eg,

     this->coeffsDict().template get<scalar>("key");

  For this common use case, the predefined getXXX shortcuts may be
  useful. Eg,

     this->coeffsDict().getScalar("key");

src/waveModels/waveGenerationModels/base/waveGenerationModel/waveGenerationModel.C

@@ -88,7 +88,7 @@ bool Foam::waveModels::waveGenerationModel::readDict
 {
     if (waveModel::readDict(overrideDict))
     {
-        activeAbsorption_ = get<bool>("activeAbsorption");
+        readEntry("activeAbsorption", activeAbsorption_);
 
         return true;
     }