To modify chat_api.
merge chat_api branch to fix segfault.
remove debugging code.
merge chat_api: change data-structure.
merge chat_data.
refactoring the code receiving chat_data.
refactoring : data receive.
bug fix: segmentation fault: cannot create directory & try to open it.
add debuggin code.
add NULL casee in set_roomlist.
debug :unkonw command\n
merge feature/SimpleChatClient.
Merge all.