Fix #6, support Chinese question mark
Remove commented line in last commit. Ruoran
add graph message support. Shasha & Zhihao
Use absolute path for PicUrl and Url. Shasha & Zhihao
Remove end tag of PicUrl in test. Fix the build. Shasha
Merge pull request #10 from winsonwq/add_graph_message_support

add graph message support. Shasha & Zhihao
Return welcome message when user subscribes. Ruoran
Refactor subscribe event. Ruoran
Merge pull request #11 from winsonwq/add_subscribe_event_msg

Add subscribe event msg
Make update_session private. Ruoran

Fix the accidental change in previous commit