Fix for the issue " libtocc::Manager should check for the existence of `base_path`"

Will it be ok if I pass "base_path" in Database() object initialization itself  rather than database_path
here : 
Database* database = new Database(database_path);
then we can append the "/TOCCFILE.DB" in Database::Database(std::string database_file) if path is correct and that makes sense also, because if path is not correct whats the meaning of initializing a database path.