dataflow_cpp: fixed cpplint warnings

dataflow_cpp/include/embb/dataflow/internal/node.h

@@ -64,7 +64,7 @@ class Node {
   static int next_process_id_;
 
   static int GetNextProcessID() { return next_process_id_++; }
-  virtual void SetSlices(int /*slices*/) {};
+  virtual void SetSlices(int /*slices*/) {}
 };
 
 } // namespace internal

dataflow_cpp/include/embb/dataflow/internal/scheduler_mtapi.h

@@ -101,6 +101,7 @@ class SchedulerMTAPI : public Scheduler {
     group_[slice]->WaitAll(MTAPI_INFINITE);
   }
   virtual int GetSlices() { return slices_; }
+
  private:
   embb::tasks::Group ** group_;
   embb::tasks::Queue ** queue_;

dataflow_cpp/include/embb/dataflow/internal/select.h

@@ -44,7 +44,7 @@ class Select
   typedef Inputs<bool, Type, Type> InputsType;
   typedef Outputs<Type> OutputsType;
 
-  Select(Scheduler * sched) : inputs_(), slices_(0) {
+  explicit Select(Scheduler * sched) : inputs_(), slices_(0) {
     inputs_.SetListener(this);
     SetScheduler(sched);
   }

dataflow_cpp/include/embb/dataflow/internal/switch.h

@@ -44,7 +44,7 @@ class Switch
   typedef Inputs<bool, Type> InputsType;
   typedef Outputs<Type, Type> OutputsType;
 
-  Switch(Scheduler * sched) : inputs_() {
+  explicit Switch(Scheduler * sched) : inputs_() {
     inputs_.SetListener(this);
     SetScheduler(sched);
   }