Make template_generator::operator() non-virtual

The API is different across the various template generators and the
method is always called directly on the given template generator type,
i.e. in a non-virtual way. Therefore, there is no need to implement this
method as virtual.

Author: FrNecas

src/domains/template_generator_base.h

@@ -46,15 +46,6 @@ class template_generator_baset:public messaget
   {
   }
 
-  virtual void operator()(
-    unsigned _domain_number,
-    const local_SSAt &SSA,
-    bool forward=true)
-  {
-    domain_number=_domain_number;
-    assert(false);
-  }
-
   virtual var_sett all_vars();
 
   inline domaint *domain()

src/domains/template_generator_callingcontext.h

@@ -27,7 +27,7 @@ class template_generator_callingcontextt:public template_generator_baset
   {
   }
 
-  virtual void operator()(
+  void operator()(
     unsigned _domain_number,
     const local_SSAt &SSA,
     local_SSAt::nodest::const_iterator n_it,

src/domains/template_generator_ranking.h

@@ -28,7 +28,7 @@ class template_generator_rankingt:public template_generator_baset
   {
   }
 
-  virtual void operator()(
+  void operator()(
     unsigned _domain_number,
     const local_SSAt &SSA,
     bool forward=true);

src/domains/template_generator_summary.h

@@ -28,7 +28,7 @@ class template_generator_summaryt:public template_generator_baset
   {
   }
 
-  virtual void operator()(
+  void operator()(
     unsigned _domain_number,
     const local_SSAt &SSA,
     bool forward=true);