* Add koolearn
koolean is an online course platform from xdf.cn
* Add duitang
duitang is an picture community as '堆糖'
* Add baijiayun
baijiayun is a live streaming cdn for education in China
* Add docin
Add docin which is a document sharing platform as '豆丁'
* Add doc88
Add doc88 which is a document sharing platform as '道客巴巴'
* Add NAT-TEST
add NAT-Test-China, a Japanese language test like j-test.
* Add category documents
this category is for documents sharing website like "docin", "doc88" and so on.
* Update geolocation-cn
Add baijiayun, duitang, category-documents-cn, koolearn and nat-test.
Remove duplicated address from geosite:cn.
