Adding initWithDictionary:withMultithreadingSupport: and adding customized database location setting for datasource

Allow to dynamically connect to a database, without using PLIST. Database location can also be customized, the database is not anymore forced to be local to the app.

        NSDictionary *dbConfig = [[NSDictionary alloc] initWithObjectsAndKeys:
                                    @"myDatabase.db", @"database",
                                    @"/Users/sample/Documents/", @"databaseLocation",
                                    @"YES", @"readonly",
                                    @"SQLite", @"type", nil];
        _database = [[ZIMDbConnection alloc] initWithDictionary: dbConfig withMultithreadingSupport:NO];