去掉将 double 映射为 sqlite text 的限制

现在 sqlite3 里，double 类型占用 8 bytes，对于一般的 double 类型的数据，也基本够用，无需以 text 来容纳

Author: NathanLi

LKDBHelper/Helper/LKDBHelper.m

@@ -625,10 +625,6 @@ - (BOOL)_createTableWithModelClass:(Class)modelClass tableName:(NSString*)tableN
 
         NSString* columnType = property.sqlColumnType;
 
-        if ([columnType isEqualToString:LKSQL_Type_Double]) {
-            columnType = LKSQL_Type_Text;
-        }
-
         [table_pars appendFormat:@"%@ %@", property.sqlColumnName, columnType];
 
         if ([property.sqlColumnType isEqualToString:LKSQL_Type_Text]) {
@@ -1554,4 +1550,4 @@ + (LKDBHelper*)getUsingLKDBHelper
 
 @implementation LKDBWeakObject
 
-@end
+@end