add default value and pk autoincrement

[joinee0208]

hi! the request include two features.

1:add property's default value.user can use like follows:
table.addIntProperty("UpdateAt").defValue("0");

2:add one more constructor.If the primary key is set to autoincrement,then the primary key column need not to be valued.as follows:

public class Demo {

    private Long id;//the id is primary key.
    private Long UpdateAt;

    public Demo() {
    }
    public Demo(Long UpdateAt) {

        if(this.UpdateAt==null)this.UpdateAt = 0l;
    }
    public Demo(Long id,Long UpdateAt) {
        this.id = id;
        if(this.UpdateAt==null)this.UpdateAt = 0l;
    }
    .
    .
    .
}