Add Snapshot feature

Add ChangeDatabase() method
Add GetDatabaseHome() and GetDatabaseFile()

src/controller/KissCount.cpp

@@ -644,3 +644,8 @@ std::vector<ExportEngine*>*  KissCount::GetExportEngines()
 
     return _exportEngines;
 }
+
+bool KissCount::ChangeDatabase(QString filename)
+{
+    return _db->ChangeDatabase(filename);
+}

src/controller/KissCount.hpp

@@ -137,6 +137,8 @@ public:
 
     void GetHistory(int month, int year, QStringList& list);
 
+    bool ChangeDatabase(QString filename);
+
 private:
     wxUI* _wxUI;
     Database* _db;