UIButtonのタイトルの位置,サイズ調整
UIButton*btn=[UIButton buttonWithType:UIButtonTypeCustom];
[btn setTitleEdgeInsets:UIEdgeInsetsMake(6.0f, 7.0f, 8.0f, 9.0f];//top margin:6.0, left margin:7.0, bottom margin:8.0, right margin:9.0