Add Delete operation in GridAccount

Fix a bug : Forgot to update stats when there is a modification

src/controller/KissCount.hpp

@@ -113,7 +113,8 @@ public:
     void GetMonthStats(int month, int year, int nbDays,
 		       std::map<int, std::vector<double> >* operations,
 		       std::map<int, double>* categories);
-
+    void UpdateStats();
+    
     std::map<int, double>* GetNotChecked(int month, int year);
     std::map<int, double>* GetVirtualAmount(int month, int year);