将自定义的标注格式转换为voc的xml格式，可用于faster rcnn训练
###Annotation Format
E:/data/image_0001.jpg 2 ChinaFlag 100 100 200 200 KoreaFlag 112 112 212 212
E:/data/image_0002.jpg 2 ChinaFlag 111 222 333 444 KoreaFlag 555 666 777 888
Note: 分隔符是Tab键
###Generated VOC xml format
VOC2012
image_0001.jpg
flickr
Fried Camels
Jinky the Fruit Bat
500
600
1
0
ChinaFlag
1
0
100
100
200
200
KoreaFlag
1
0
112
112
212
212